Volume 4 Issue 4
Md. Khairul Amin, Md. Ahmadul Islam , Farzana Akter , Md. Nazrul Islam
doi:10.5455/faa.72409 pp: 1089-1096
The study was concerned with the kinetics of dehydration of jackfruit and mango pulp and their use for the development of mixed leather. Kinetics study showed that jackfruit pulp dried faster than mango pulp. The chemical composition of fresh jackfruit and mango pulp showed that moisture, ash, protein, fat, vitamin -C, acidity, pH and total soluble solids content were found 74.23%, 0.86%, 1.55%, 0.60%, 5.04 mg/100g, 0.224% (wb), 5.41 and 25.0% for jackfruit pulp, whereas for mango pulp, the contents are 80.1%, 0.45%, 1.2%, 0.70%, 24.2 mg/100 g, 0.48% (wb), 3.79 and 18.0% respectively. During mechanical drying, it was shown that drying rate decreased with the increase in thickness and for fresh jackfruit and mango pulp, values of index ‘n’ were 0.38 and 0.20 at 60°C respectively, whereas for steam blanched jackfruit and mango pulp, value of index ‘n’ were 0.38 and 0.29 at 60°C respectively and these were lower than 2 as predicted by the Fick’s 2nd law of diffusion. The activation energy (Ea) was calculated as 3.12, 2.786, 2.90 and 2.786 Kcal g-1 mole, respectively for the fresh jackfruit, fresh mango, steam blanched jackfruit and steam blanched mango pulps respectively. The organoleptic taste test showed that sample 401 (Fruit pulp with sugar and KMS) secured highest score.
Key words: Dehydration, Jackfruit pulp, Mango pulp, Mixed leather and Activation energy
Md. Al Ekram , Md. Harun Ar Rashid, Md. Abdur Rahim, Tahmina Akter
doi:10.5455/faa.60378 pp: 1081-1088
The study was conducted at the FTIP Germplasm Centre of the Bangladesh Agricultural University (FTIP BAU-GPC), Mymensingh during the period from July 2017 to October 2018 to find out the effects of fruit thinning on the off-season quality guava production. The two factor experiment consisted of two guava varieties viz. Swarupkathi and BAU Peyara-5, and six type fruit thinning namely no fruit thinning (control), 20% fruit thinning, 40% fruit thinning, 60% fruit thinning, 80% fruit thinning and 100% fruit thinning. The experiment was carried out in a randomised complete block design (RCBD) with three replications. Guava varieties and fruit thinning both had significant effects on both on-season and off-season guava production. During on-season, Swarupkathi showed superiority over BAU Peyara-5. During off-season, yield of Swarupkathi was 1.73 kg plant-1, whereas BAU Peyara-5 produced only flowers but no fruit due to flower dropping in off-season. In respect of thinning effect during on season 6.05 kg fruit per plant was produced with 80% fruit thinning, which was the best in on-season. During off-season 1.51 kg fruit per plant was produced with 100% fruit thinning of previous season, which was the best in off-season. For combined effect during on-season, Swarupkathi produced 8.60 kg fruit per plant at 80% fruit thinning which was found to be better result in Swarupkathi after different times of thinning practices, whereas BAU Peyara-5 produced 3.50 kg fruit per plant at 80% fruit thinning which was found to be better result in BAU Peyara-5 after different thinning practices. During off-season, Swarupkathi produced 3.01 kg fruit per plant with 100% fruit thinning of previous season, which was found to be better result in Swarupkathi, while BAU Peyara-5 produced few flowers (3) and did not produce any fruit due to flower dropping.
Key words: BAU Peyara-5, percent fruit thinning, guava, productivity, Swarupkathi, TSS
Identification of plant growth promoting antagonistic bacteria against Xanthomonas oryzae pv. oryzae in Bangladesh
Md Rashidul Islam, Noor E Tajkia Islam, Papia Sharmin Juthy, Md Mahbubul Haque, Md Mahfujur Rahman
doi: 10.5455/faa.67224 pp: 1068-1080
The purpose of this work was to isolate and identify the plant growth pro- moting bacteria from rice phylloplane and rhizosphere that antagonistic to X. oryzae pv. oryzae. Rice phylloplane and rhizosphere bacteria were isolated from the surface of rice leaves and stem as well as from the soil attached to the roots of rice plants, respectively. The antagonistic activity of these isolated bacteria was determined by dual culture method. The antagonistic bacterial isolates were identified by sequencing of 16SrDNA. The activities related to plant growth promotion were determined by In- dole Acetic Acid (IAA) production, siderophore and phosphate solubi- lization assay.The promotion of plant growth was assessed by the deter- mination of root length, shoot length and vigor index. Sixteen bacte- rial isolates were identified as antagonist to X. oryzae pv. oryzae out of 300 bacterial isolates by dual culture method. The maximum growth in- hibition (33.5 mm) of X. oryzae pv. oryzae was recorded in plate inocu- lated with BDISOB05P while the minimum growth inhibition (5 mm) was recorded by BDISOB98P and BDISOB272R. The moderate growth inhibi- tion was recorded in BDISOB241P, BDISOB16P, BDISOB306R, BDISOB242P, BDISOB220R, BDISOB04P, BDISOB258R, BDISOB219R, BDISOB221R, BDISOB275R, BDISOB283R and BDISOB61R. 16S rDNA sequencing was used to identify the bacterial isolates which were antagonistic. The bacterial iso- lates were identified BDISOB04P as Pseudomonas putida, BDISOB05P as Pseu- domonas putida, BDISOB16P as Bacillus sp., BDISOB98P as Stenotrophomonas maltophilia, BDISOB241P as Burkholderia sp., BDISOB242P as Burkholderia gladioli, BDISOB219R as Pseudomonas taiwanensis, BDISOB220R as Serratia sp., BDISOB221R as Pseudomonas sp., BDISOB222R as Pseudomonas plecoglossicida, BDISOB258R as Pseudomonas putida, BDISOB272R as Stenotrophomonas mal- tophilia, BDISOB275R as Pseudomonas putida, BDISOB283R as Pseudomonas fluorescens and BDISOB306R as P. putida. Eight antagonistic bacterial isolates produce IAA, sixteen bacterial isolates were able to produce siderophore and nine bacterial isolates were found to show phosphate solubilizing capabil- ity. The results of plant growth promotion activities indicating that these bacterial isolates can increase the root growth, shoot growth and vigor index.
Keywords: Plant growth, antagonistic bacteria, X. oryzae pv. oryzae
Md. Moshiur Rahman, Md. Monirul Islam, Md. Mahamudul Hasan, Md. Delwar Hossain
doi: 10.5455/faa.71090 pp: 1060-1067
An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh (latitude of 24.75°N, longitude of 90.5°E and altitude l8 m) during 5 July to 21 November, 2017 to find out the effect of nitrogen rates on the yield performance of two short duration transplant monsoon (Aman) rice varieties. The experiment included two rice varieties viz. Binadhan-7 and BRRI dhan49 and six rates of nitrogen viz. 0, 30, 60, 90, 120 and 150 kg N ha-1 in a split- plot design with three replications. The result revealed that grain yield was significantly influenced by rate of nitrogen but not by variety and interaction between variety and nitrogen rates. The highest yield was achieved at 120 kg N ha-1 which was similar with 90 kg N ha-1. The highest yield was attributed to higher number of effective tiller hill-1 at higher nitrogen rates. The field trial showed the highest grain yield for Binadhan-7 and BRRI dhan49 for90-120 kg N ha-1. However, the estimated optimum rate of nitrogen from response analysis for Binadhan-7 and BRRI dhan49 were 107 and 103 kg N ha-1, respectively. Present study reveals that the highest yield of the two short duration rice varieties Binadhan-7 and BRRI dhan49 could be obtained by applying 107 and 103 kg N ha-1, respectively.
Keywords: Monsoon rice, nitrogen rate optimization, short duration variety, quadratic response model
Md. Murad Hossan Chowdhury, Md. Amirul Islam, Md. Habibur Rahman, Md. Abdur Rahim, Md. Atikuzzamman, Maria Akter Sathi
doi:10.5455/faa.59383 pp: 1054-1059
A field research was conducted at the Horticulture Farm of Bangladesh Agricultural University, Mymensingh during the period between November 2011 and February 2012 to determine the yield performance of some exotic potato accessions/cultivars. The experiment was laid out in randomized complete block design (RCBD) with three replications. The experiment comprised of six (6) different exotic potato accessions viz. i) AC10064, ii) AC10076, iii) AC10097, iv) AC10109, v) AC10123, vi) AC10190 and one cultivar Cardinal as control. Various data were recorded on yield and different yield contributing characters. The lowest days required for plant emergence at accession AC10109 (6.25) and the maximum days required at variety Cardinal (10.02). The highest tuber length (7.11 cm) and diameter (5.70 cm) were found in the accession AC10109 and lowest length (5.85 cm) and diameter (3.81 cm) of tubers were found in the variety Cardinal. The maximum (274.74 g) and the minimum (130.11 g) yield of tubers per hill were found in accession AC10109 and Cardinal, respectively. The maximum yield of tubers per hectare was obtained from the accession AC10109 (29.31 t/ha) closely followed by AC10064 (28.88 t/ha) and the minimum yield of tubers was obtained from the accession Cardinal followed by AC10190 (15.97 t/ha). Considering the yield performance, potato accession AC10109 was the best performer followed by AC10064 and performed better than popular existing variety Cardinal, therefore these two accessions may be considered for further multi-location trial before final recommendation.
Keywords: Potato, accession, growth, yield
Olivier Ndayitegeye, Japheth Ogalo Onyando, Romulus Okoth Okwany, Johnson Kisera Kwach
doi: 10.5455/faa.70723 pp: 1047-1053
Water is a limited source with no known substitute. The decrease in precipitations leads to less and less soil water available to crops, hence, proper management of agricultural water is of utmost importance. This study assessed the effects of three irrigation levels (IL) and three irrigation intervals (II) on the vegetative growth of East Africa Highland Banana (Musa spp., AAA-EAHB), cv Ng’ombe. The experiment involved a rain-shelter experiment comprising a randomized complete block design (RCBD) plots. Three levels of water applications (100%, 90% and 80% of evapotranspiration) at 4, 6 and 8 days as irrigation intervals were applied. FAO-CROPWAT 8.0 model was used to calculate irrigation water requirements based on crop, soil and climate data of the study area. Data collected over a period of 12 months were analyzed and showed that water application could be reduced to 90% of optimal water requirement at 4 days irrigation interval without significantly affecting the important vegetative growth parameters at a level of significance of α≤0.05. The important vegetative crop parameters considered and their measurements in mid-stage are girth of the stem at the base (70.6±0.9 cm), leaf area (5587.9±84.4 cm2) and plant heights (297.3±4.2 cm). Local Climate Estimator software (New_LocClim) was used to provide approximations of climatic conditions because actual data required were not available on the site. Deficit irrigation combined with short irrigation intervals on banana cultivation is a way of saving water without affecting vegetative growth and most probably without any significant reduction of the yield. Reducing irrigation water in banana plantations will save the amount of water used in agriculture especially in areas that receive low precipitations.
Keywords: Deficit irrigation, banana, growth parameters, CROPWAT
Economics of banning Hilsa fishing and its impact on the fishermen’s income in Chandpur Sadar Upazila of Bangladesh
Md Saidur Rahman, Flora Begum, Md Mazibur Rahman, Nusrat Jahan, M Nahid Sattar
doi: 10.5455/faa.71026 pp: 1038-1046
Hilsa fish population had been declining due to the fishing of the juvenile fish and fishing during the breeding seasons. So, restrictions have been imposed on the fishing of jatka during certain times and on all kinds of Hilsa fishing during certain times of the year. However, the Hilsa fishermen are poor and these restrictions may adversely affect their income. This study aimed to understand the impact of seasonal banning of Hilsa fishing on the fishermen’s income in Chandpur Sadar Upazila. The study was based on a field survey where primary data were collected from 40 fishermen and secondary data were collected from different reports, published and unpublished documents, journal articles, etc. Changes in income of fishermen were observed through benefit-cost analysis of fish farming. Factors affecting changes in income because of the ban were analyzed through regression analysis. The present study revealed that the BCR of Hilsa fishing before banning season was 1.20. The total cost of Hilsa fishing per day was Tk. 2972. The gross return per day was Tk. 3591 in peak season. The net return of Hilsa fishing per day was Tk. 618. The study also revealed that per day income of Hilsa fishermen during banning period was about Tk. 182. The regression analysis found that subsidy, alternative job, other types of fish catch, fishing hour, and experience of Hilsa fishermen, all of these factors had a negative impact on the difference in income before and during the ban while, the quantity of Hilsa fish caught had a positive impact. The study also found that the Hilsa fishermen were facing various financial, technical, marketing and social problems. The study concluded that steps should be taken to provide alternate income support to the Hilsa fishermen, especially during ban and lean period.
Keywords: Hilsa fishermen, fishing ban, fishing income, economic impact, Bangladesh
Compatibility of ten isolates of Beauveria bassiana (Balsamo) Vuillemin with four commonly used fungicides in Thailand
Patcharin Krutmuang, Sarayute Pittarate, Aroja Rahman, Julius Rajula, Malee Thungrabeab
doi: 10.5455/faa.70566 pp: 1032-1037
The use of Beauveria bassiana (Balsamo) Vuillemin (Phylum: Ascomycota: and Order: Hypocreales) has greatly increased due to its broad spectrum of pathogenic activity. This fungi has been studied intensively for the purpose of developing mycoinsecticides that can be integrated with other agrochemicals in the management insect pests in rice fields. Additionally, its use in crops other than rice is being studied. This study investigated the effect of four fungicides viz. mancozeb, propineb, propiconazole, and pifenoconazole, on the growth of 10 isolates of B. bassiana under laboratory conditions. Malt extract agar (MEA) amended with the fungicides at two rates (recommended and half-rate) where recommended rates were as follows: mancozeb (15 g 20 L−1 of water), propineb (55 g 20 L−1 of water), propiconazole (25 mL 20 L−1 of water) and difenoconazole (40 m 20 L−1 of water) were used to culture the isolates of the fungus. It was observed that propiconazole and difenoconazole consistently exerted a strong inhibitory effect on the mycelial growth of the B. bassiana isolates. On the other hand, the isolates of B. bassiana tested exhibited low to moderate sensitivity to mancozeb and propineb. B. bassiana isolate BCMU 2 displayed low to moderate sensitivity to mancozeb, propineb, and difenoconazole. This study suggests that mancozeb and propineb may have the potential for use in combination with B. bassiana in integrated pest management programs for simultaneous control of insect pests and plant diseases.
Keywords: Beauveria bassiana, entomopathogenic fungus, fungicides, difenoconazole, mancozeb, propiconazole, propineb
Management of brinjal shoot and fruit borer (Leucinodes orbonalis Guen.) using selected bio-rational insecticides
Md. Simon Islam, Md. Abdur Razzak Choudhury, Md. Abdul Maleque, Md. Fuad Mondal, Kamrul Hassan , Ahasan Ullah Khan
doi: 10.5455/faa.55331 pp: 1025-1031
An experiment was undertaken to know the effectiveness of different bio-rational insecticides for controlling brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) under field conditions during winter season 2017-18. The different treatments were Bioneem 1% EC (Azadirachtin 1000ppm @1mlL-1 (T1) Noclaim 5 SG (Emamectin Benzoate) @1mlL-1 (T2), Tracer 45 SC (Spinosad) @0.4 1mlL-1 (T3), Suntec 1.8 EC (Abamectin) @1.2 1mlL-1 (T4) and untreated control (T5). The results revealed that the treatments Spinosad (T3), Abamectin (T4) and Emamectin Benzoate (T2) were effective to suppress brinjal shoot and fruit borer infestation in brinjal field. The rate of shoot infestation was observed 6.25% and 26.01% in Spinosad (T3) treated and control plot, respectively. The lowest fruit infestation (6.98%) by number and (9.32%) by weight was recorded in Spinosad (T3) treated plot. Reduction rate of fruit infestation over control was 82.82, 51.19, 41.15 and 38.17% by number and 66.11, 43.75, 33.13 and 24.44% by weight in Spinosad (T3), Emamectin Benzoate (T2), Abamectin (T4) and Azadirachtin (T1), treated plot, respectively. The yield in different treatments ranged from 22.02 – 32.52 t/ha. Healthy fruits yield increase over control varied from 19.36 to 85.46%, where the highest increase was found in Spinosad (T3) treated plot and the lowest in Azadirachtin (T1). The highest adjusted net return and Benefit Cost Ratio of Tk. 2,61564 and 11.08, respectively were obtained from Spinosad (T3) treated plot. The lowest Benefit Cost Ratio was 2.66 in Azadirachtin (T1) treated plot. Among the four bio-rational inecticides Tracer 45 SC (Spinosad) showed the highest efficacy and it could be used against brinjal shoot and fruit borer in brinjal production.
Keywords: Brinjal, shoot and fruit borer, bio-rational insecticides, management
Traits association, path analyses and multiple linear regression estimates in rice (Oryza sativa L.)
Joynulalam Talukder, Md. Abdullah Al Bari, Mirza Mofazzal Islam, Majharul Islam, Rashedullah Jewel, Israt Jahan
doi: 10.5455/faa.60679 pp: 1019-1024
Rice yield is the ultimate target of any plant breeder that needs to be increased for fulfilling the growing population demand. Yield is a complex character in nature which is directly and/or indirectly influenced by other traits. As a result, screening of segregating breeding lines based on only yield may mislead selection in the breeding programs. So the research objectives were to measure the association existed among yield and yield related traits, measuring the direct and indirect effects of yield associated traits on grain yield and estimate the influence of secondary traits in determining yield of rice. Forty seven rice genotypes including BINA dhan10, BINA dhan17, NERICA mutant and rest developed genetic materials were planted following randomized complete block design using three replications at BINA complex from July 2015 to December 2016. The statistical program MSTAT-C, BASICA and multiple linear regression analyses model implemented in R were used to analyze the data. Traits association analyses suggested that yield plant-1 had highly significant and positive association existed with plant height (rp: 0.577, rg: 0.591) followed by active tillers number plant-1 (rp: 0.372, rg: 0.364) and tillers number plant-1 (rp: 0.337, rg: 0.342) and negative significant association with days to first flowering (rp: -0.095, rg: -0.094). Plant height had the highest positive direct effect (0.685) and tillers number plant-1 (-0.364) showed maximum negative direct effect towards yield plant-1 as revealed from path analyses. The multiple linear regression analyses showed that the change of 1cm of plant height could influence about 0.19 gm rice yield plant-1 as per Model 1 and 0.16 gm rice yield plant-1 as per Model 2. Measured plant height, active tillers number plant-1 and days to first flowering could be more influencing traits for selecting breeding lines in segregating generations to develop high yielding of rice genotypes.
Keywords: Characters relationship, path coefficient, regression analyses and Rice.
Integrated application of banana peduncle-derived biochar and fertilizer affect soil physicochemical properties and plant nutrient uptake
Lawrence Tatanah Nanganoa, Godwin Sendze Yinda, Ebonlo Jeremiah Ndande, Patrick Valerie Mounoumeck, Lewis Dopgima Levai, Justin Nambangia Okolle, Christopher Ngosong
doi: 10.5455/faa.64828 pp: 1008-1018
Spreading banana peduncle residues in banana plantations to enhance soil physicochemical properties is common practice and has also been identified as vector of mealybug re-infestation. Producing biochar from banana peduncle residues could reduce infestation, improve soil fertility and promote plant growth and sequester carbon. Hence this greenhouse study was conducted to assess the effects of banana peduncle-derived biochars produced at pyrolysis temperatures of 300°C (BC300) and 500°C (BC500), and their combination with inorganic fertilizer on soil nutrient status, plant growth and nutrient uptake in banana plantlets grown in soil-filled polythene bags. Six treatments; control–no input, 30g BC300, 30g BC500, 30g inorganic fertilizer, 15g BC300 + 15g inorganic fertilizer, and 15g BC500 + 15g inorganic fertilizer were applied. BC300 had significantly higher yield, volatile matter, nitrogen and moisture content, whereas pH, fixed C, Ca, K and ash contents were lower as compared to BC500. Post-planting soil parameters (pH, organic C, available P, exchangeable K, Mg, and ECEC) increased significantly for the biochar treatments (BC300 and BC500) as compared to control and pre-planting soil. Integrated biochar and inorganic fertilizer significantly increased organic carbon and pH as compared to inorganic fertilizer alone. Significant negative correlations demonstrated the effects of sole biochar on soil C/N ratio and pH, which might have reduced nutrient (N and K) uptake and accumulation in banana leaves, while pH also affected leaf Mg. Principal Component Analysis (PCA) also revealed greater leaf nutrient uptake and accumulation in relation to inorganic fertilizer input alone or in combination with biochar, as compared to biochar alone. The combination of biochar with reduced-dose of fertilizer enhanced the potency of the inorganic fertilizer with BC500 as the most effective.
Keywords: Banana peduncle biochar, Banana plantlets, fertilizer, plant nutrition, pyrolysis
Preparation of purified peste des petits ruminants (PPR) virus antigen from a local isolate of Bangladesh
Ashrafun Naher Luna , Fardina Sultana Sumi, Jahan Ara Begum, Md. Mushfiqur Rahman, Mohammad Rafiqul Islam, Emdadul Haque Chowdhury
doi: 10.5455/faa.63311 pp: 1004-1007
Peste des petits ruminants (PPR) is the number one killer disease of small ruminants especially sheep and goats. The disease is presently considered as one of the major threats to about 22 million small ruminant population of Bangladesh with 80-100% mortality in an outbreak and ultimately causes severe losses to small ruminant production. To control and eradicate PPR disease from Bangladesh quick detection and diagnosis is necessary. In field condition, PPR can be diagnosed by serological test and further confirmed by RT-PCR in laboratory. But all the tests are too expensive. The present study was performed to prepare purified Peste des petits ruminants virus (PPRV) antigen which can be used for the development of a quick and cheapest diagnostic ELISA kit. A recombinant tissue culture adapted strain of PPRV was propagated in Vero cell culture, the virus was pelleted by high speed centrifugation and the concentrated virus was purified by density gradient centrifugation using a discontinuous gradient of 30% and 60% sucrose. For further confirmation the purified virus was subjected to RT-PCR. The present method of preparing purified antigen appeared to be quite efficient as a distinct clear band of purified virus was found at the interface of 30% and 60% sucrose following density gradient centrifugation. In RT-PCR, a fragment of the Fusion (F) gene of purified PPRV was amplified with the expected band size of 448 bp. The purified PPR viral antigen may be used as potential diagnostic antigen.
Keywords: PPRV, antigen, density gradient centrifugation
Influence of pre-harvest spraying of gibberellic and boric acids on the growth and fruit characteristics of pomegranate fruit cv. Shishe-Kab
Farid Moradinezhad, Mina Mohammadian Moghadam, Mehdi Khayat
doi: 10.5455/faa.63810 pp: 995-1003
Influence of foliar application of gibberellic acid and boric acid on fruit growth and characteristics of pomegranate cv. Shishe-Kab was carried out in the research orchard of Birjand University during 2017 and 2018 seasons. The experiment conducted in a randomized complete block design with six replications. Experimental treatments were control (spray with distilled water), gibberellic acid at 50 and 150 mg L−1 and boric acid at 200 and 600 mg L−1. Gibberellic acid and boric acid sprayed three times at one-month interval started from late May, to July during fruit growth and developmental stages. At mid-October fully mature fruits were harvested and fruit quality and quantity were assessed in the laboratory of Department of Horticultural Science, University of Birjand. Results of this study indicated that foliar application of gibberellic acid and boric acid decreased chroma of pomegranate peel in 2017 and 2018, while it increased hue of pomegranate peel. Foliar application of boric acid significantly increased length, volume, fresh weight, and juice content of pomegranate fruit. However, peel thickness and sunburned were significantly increased by application of gibberellic acid in both studied years. Total acidity was significantly increased by application of gibberellic acid in 2018 season. Leaves chlorophyll content increased by application of 150 mg L−1 gibberellic acid and 200 mg L−1 boric acid in both seasons. Application of 50 mg L−1 of gibberellic acid significantly increased total soluble solid of pomegranates in 2017 and 2018. This result showed that foliar application of gibberellic acid and boric acid had positive effects on quality and quantity properties of pomegranate fruits cv. Shishe-Kab cultivar and it may be used to improve fruit production. However, further studies need to determine the exact application time and concentration for practical application.
Keywords: Acidity, boron, chlorophyll, gibberellin, sunburned
Farzana Mustafa Era, Mohammad Sharif Raihan, A K M Aminul Islam
doi: 10.5455/faa.48652 pp: 978-994
Papaya (Carica papaya L.) is a polygamous species and the plants are extremely diverse in their sexual systems. Three sex types are available in papaya viz., male, female and hermaphrodite and are controlled by a single gene with three alleles (m, M1, M2). The genotypes represent gynoecious, androecious and hermaphrodite individuals. Ninety percent of freshly dispersed pollen grains were viable in summer but viability dropped to about 45% in some lines and as low as 4.5% in others in winter. The extremes of humidity reduce the storage life of papaya pollen but under ideal (artiﬁcial) storage conditions it potentially remains viable for about 5-6 years. The stigma become receptive two days before anthesis and continued up to ﬁve days after anthesis but began to decline gradually upto ﬁve days after anthesis. Papaya plants produce fruit either through cross-pollination or self-pollination or parthenocarpy depending on their sex types. On an average 1,000 seeds are found in a single fruit, indicating that 1,000 viable pollen grains may fertilized receptive stigma. The sex types in papaya is found to be related with several morphological characters. Seed coat color, petiole thickness, stems color worked as a morphological marker for sex determination in papaya. The black and dark brown seed coat color exhibited higher frequency of the female and hermaphrodite plants. The range of 54–60° petiole orientation, 3.7–4.2 cm petiole thickness and 9.4–10.4 cm petiole length gave higher percentage of female and hermaphrodite plants. On the other hand, unique purple stem color was reported to express as hermaphrodite plants. In case of chemical identiﬁcation of sex in papaya Almen reagent test, Ammonium molybdite test, Titanous chloride test gave 71%, 60% and 55% accuracy of femaleness respectively. Ethrel gave the most expected number (46.67%) but excessive Ethrel may also cause higher number of male. In case of Kinetin and IBB 100 ppm and 200 ppm gave higher percentage of female. Environment may also affect the sex expression of papya. In along with these, several molecular markers may also be used to identify the sex type of papaya. Among them SSR and RAPD is mostly familiar and successful.
Keywords: Carica papaya, polygamous, gynodioecious, hermaphrodite, pistillode, sexual lability