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Open Access
Heterosis breeding in sesame (Sesamum indicum L.).
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Gayathri, G; KAU; Dijee, Bastian
The study entitled ‘Heterosis breeding in sesame (Sesamum indicum L.)’ was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara. The objectives of the study were to collect and evaluate different genotypes of sesame for morphological traits and yield attributes, to identify useful parents producing heterotic crosses and developing hybrids in sesame. The study also intended to develop male sterile lines in sesame through interspecific hybridization with Sesamum malabaricum. Sesamum indicum and Sesamum malabaricum accessions were collected from Kerala and Tamil Nadu and evaluated for their morphological traits. Wide range of variation was noticed for characters like plant height, number of days to flowering and seed yield per plant which contributed maximum to genetic divergence. The genotypes studied were grouped into six clusters. High genotypic coefficient of variation (GCV) was recorded for number of capsules per plant, plant height, seed yield per plant and number of branches per plant. High heritability with high genetic advance as per cent of mean was recorded for number of days to flowering, plant height, number of branches per plant, number of capsules per plant and seed yield per plant. This indicates that the characters are governed by additive gene effects and selection for these traits will be effective. Association analysis revealed that seed yield per plant was correlated to plant height, number of capsules per plant and number of days to flowering. Path coefficient analysis indicated maximum positive direct effect by number of capsules per plant, capsule length, plant height and 1000 seed weight on seed yield per plant. In order to develop hybrids, fourteen parents were selected based on the per se performance of the genotypes. They were crossed in line X tester mating design. Forty eight hybrid combinations obtained were raised in the field along with the parents and evaluated for their heterosis and combining ability effects. Parental genotypes AVTS-06-5, AVTS-06-10, IVTS-06-12, KYM-1, Tilak and TMV-6 were identified as high combiners based on general combining ability (gca) effects. Two combinations viz. AVTS-06-5 X KYM-1 and IVTS-06-12 X TMV-3 had significant values of per se performance, specific combining ability (sca) effects and standard heterosis for seed yield per plant. They can be evaluated for their hybrid vigour over locations and seasons. The crosses AVTS-06-5 X TMV-3, AVTS-06-5 X TMV-6 and TCR 3279A X KYM-1 have been identified as potential cross combinations for isolation of promising segregants as the parents involved in these crosses had high significant gca effects for seed yield per plant but the hybrids recorded non significant sca effects. Interspecific hybridization between S.malabaricum and S.indicum was attempted to develop male sterile lines. Seed set was noticed in three interspecific hybrids which failed to germinate due to embryo abortion. Hence these embryos were rescued and raised in vitro to obtain the hybrids.
Open Access
Combination breeding for high protein cowpea (Vigna unguiculata L. Walp)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Sarath, P S; KAU; Jiji, Joseph
Cowpea (Vigna unguiculata L. Walp) is one of the most important legume crops grown in India. It is a versatile pulse crop owing to its nutritional value, weed smothering nature, drought tolerant characters, soil restoring properties and multi-purpose uses. Protein deficiency has been reported to be one of the main nutritional problems in the developing world. About one billion people are reported to be suffering from protein deficiency and malnutrition worldwide. Studies have revealed that protein content in cowpea grain ranges between 18 to 40 per cent depending on the genotypes. Identifying high yielding varieties of cowpea with high protein content will not only contribute to food security and alleviate poverty but could also contribute to the alleviation of protein deficiencies. Review on the earlier research pointed to poor emphasis on the genetic improvement of cowpea for improved protein content. Hence, the present study was envisaged to combine the high protein trait with high yielding genotypes. The study was grouped under three experiments, i) Evaluation of cowpea genotypes, ii) Hybridisation of the selected genotypes in line x tester design, iii) Evaluation of F1 hybrids. The experiments were conducted at College of Horticulture, Kerala Agricultural University, Vellanikkara during 2014-2015. All the crop management practices were followed as per KAU (2011). Evaluation of cowpea genotypes revealed that there was wide variability for all the traits studied except branches per plant among bushy and semi trailing types of cowpea. In trailing type, variability was observed for plant height, number of pods per plant, pod weight grain yield per plant and seed protein content. Among the twenty two genotypes evaluated, ten genotypes that exhibited a protein content of above 25 per cent were selected for hybridization programme. The selected genotypes (Vellayani Jyothika, Bhagyalakshmi, Anaswara, Kanakamony, Lola, Vyjayanthi, AV-5, PKB-3, PKB-4 and Sharika) were hybridized in line x tester (6 x 4) design. High magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance was observed for plant height, grain yield per plant and length of pods were observed in parents and hybrids suggesting scope for genetic improvement of these traits through selection. Seeds per pod and protein content exhibited low PCV and GCV but high heritability and low genetic gain, indicating that these traits were governed by non-additive gene action and therefore breeding method other than simple selection is required. Combining ability analysis revealed that higher magnitude of specific combining ability (SCA) variances than the general combining ability (GCA) variances for the traits like pods per plant, length of pod, test weight, grain yield per plant and seed protein content indicating preponderance of non-additive gene action in the inheritance of these traits. Higher estimates of GCA variances over SCA variances for plant height, days to flowering, days to first harvest, days to last harvest, pod-weight and seeds per pod implies the preponderance of additive gene action in controlling these traits. The hybrids were ranked based on mean value, sca effects and estimates of heterosis for the traits like days to flowering, pods per plant, seeds per pod, test weight, grain yield per plant and protein content. Four hybrids with the lowest scores were selected. Hybrids H2 (Vellayani Jyothika x PKB-3), H10 (Anaswara x PKB-3), H11(Anaswara x PKB-4) and H12 (Anaswara xSharika) were found to be the most promising. The transgressive segregants with high yield and protein content can be identified on further evaluation of the segregating population from the above hybrids
Open Access
Invitro propagation in ashoka : saraca asoca (Roxb.) de wilde.
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Brindha Devi, I; KAU; Sreenivasan, E
Asoka (Saraca asoca) is an important medicinal and ornamental tropical tree currently facing the threat of extinction due to overexploitation of trees occurring in forests and other natural habitats. Unscientific and destructive extraction of bark from trees has lead to acute shortage of raw bark by ayurvedic industries. Hence, the International Union for Conservation of Nature and Natural Resources (IUCN) has listed this species under ‘globally vulnerable’ category. It is also enlisted among the 36 threatened and endangered medicinal plants of India. It is considered as the sacred tree of buddhists and Hindus. Literally the term ‘asoca’ means ‘sorrow-less’ and the tree is believed to remove the grief and unhappiness. The tree has immense medicinal properties. Its bark is considered as the primary medicinal part. Due to its acute short supply compared to its demand, various development and research activities are being prioritized to conserve, utilize and improve this species. It is mainly propagated by seeds. Due to heterozygous and cross pollinated nature of the species, it never gives a true to type progeny. Therefore the present study was undertaken to standardize the technique of in vitro propagation of Saraca asoca. Standardization of suitable explants, surface sterilization procedures and culture establishment protocol, Induction of multiple shoots and Elongation of root, hardening and planting out are the major objectives of the study. Nodal segment, Internodal segment and shoot tip were the three explants tried. Various surface sterilization procedures were tried using Chloramphenicol, ethyl alcohol, 0.1% mercuric chloride and combination of ethyl alcohol and mercuric chloride in various concentration and duration, using nodal segments as explant. Surface sterilization using 70% ethyl alcohol for 3 minutes followed by 0.1% mercuric chloride for minutes proved to be the best, which gave the maximum survival percentage of 80. The next part of the study was standardisation of suitable explants for culture establishment. Among the three explants, Nodal segments gave maximum response of 60 per cent in ½ MS medium with BAP 0.5mg/l. This was followed by shoot tips in the same medium, which gave 10 per cent response. Internodal segments did not respond in any of the media used. Standardisation of basal media for culture establishment was done using nodal segments as the explants. Three media supplemented with BA 0.5 mg.l-1 were tried viz. MS, Half strenght MS, Woody plant media. Among the three, ½ MS media was identified as the best basal medium followed by MS medium. No response was seen in WPM medium. Culture establishment as well as Shoot bud initiation was attempted in ½ MS and MS media with various growth regulator combinations. Maximum response of 60 per cent was obtained in ½ MS medium containing BAP 0.5 mg/l followed by 30 percent in the same medium containing BAP 1.5 mg/l. There were no response with 2,4-D. The response obtained was callusing in all cases. Induction of multiple shooting was tried in ½ MS medium supplemented with BAP, and Kn alone as well as combinations of BAP, IAA at various concentration. Here highest response of 30 per cent of single shoots was recorded in ½ MS media containing BAP 0.5 mg/l. Response was in the form of single shoot. The single shoots with a mean length of about 1.5mm after one week of growth was obtained. With BAP 2.0 mg/l, single shoots were produced in about 5% of cultures within 54 days. Effect of Kn in various concentration ranging from 0.5 to 2.0 mg/l was found to be low in shoot induction. The maximum length of shoot of about 1.6 cm was recorded in combination of BAP 0.5 mg/l and IAA0.5 mg/l. Various combinations of IAA and IBA at different concentrations were tried for rooting of in vitro shoots. However there was no response in any of the combinations tried.
Open Access
Reproductive biology of water lily (Nymphaea nouchali Burm.f.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2012) Fahida, P K; KAU; Presanna Kumari
Water lilies are a group of fascinating aquatic perennial herb belonging to the genus Nymphaea. Among the different species of Nymphaea, Nymphaea nouchali is one common in south India. This species is commonly known as blue water lily, blue star water lily or star lotus. The plant is historically and functionally significant since it is associated with our culture and tradition. This species which forms an important constituent of aquatic flora possesses immense medicinal and ornamental values. Despite of its immense potentialities, water lily has received very little attention of crop improvement workers. Information on developmental pattern and reproductive biology which is fundamental for crop improvement programmes is lacking in this plant. Hence this investigation entitled ‘Reproductive biology of water lily (Nymphaea nouchali Burm.f.) was under taken up with the objective of elucidating the reproductive biology and developmental pattern of flowers and fruits in Nymphaea nouchali. Two flower colour variants of Nymphaea nouchali- blue and white types maintained in cement tanks were selected for the study. The study was conducted during 2010-2012 in the Department of Plant Breeding and genetics, College of Horticulture, Vellanikkara. The leaves of both the colour variants are simple, orbicular with sub-peltate lamina and deeply cleft near to the petiole base. The petiole of both the type was long, glabrous and brownish in colour with lamina floating on the water surface. The blue type was significantly superior to the white type for mean length of leaf as well as means width of leaf at middle and tip. In both the types it took almost six days for the flower bud to reach the water surface and the flower opening occurred nearly three days after the bud reaching the water surface. Even after the flower opening the pedicel elongation continued in both the types to an extent of 4 cm. Maximum growth rate of the pedicel was observed on the day just prior to the flower opening. The white type produced longer flower bud and thus larger flowers when compared to blue type. However the circumference of the flower bud was more for blue type. The flowers of both the types were faintly fragrant. The flowers opened in morning and closed in the evening hours and again opened on next day. The opening time of the flower varied from 7.30 am to 9.45 am. The closing time varied from 5.15 pm to 6.15 pm. Bright and sunny days favoured early opening of the flower. The blossom life was three days for blue type where as it was four days in white type. The flowers were produced throughout the year on an average of 3 to 4 days interval in both the types. Hence it can be well recommended for water gardens. The flowers were found to be solitary, pedicellate, and complete with various floral whorls in spiral fashion on the floral axis. Significant variability was observed on various floral characters among the two types. Each stamen consisted of a filament, anther and a sterile appendage at the tip. The initiation of dehiscence occurred by the longitudinal splitting of the anthers in both the types. The pollen dehiscence occurred only after complete opening of the flower. The stigma receptivity started 17 hours before flower opening and the receptivity was retained up to 20 hours after flower opening. Honey bees, house flies and weevils were found to be the major insects visiting the flowers. Several dead insects were observed in the stigmatic cup of both the types indicated the insectivorous nature of the flower. The pollen grains were found to be round, yellow in colour and monocolpate with reticulate exine in both the colour variants. No fruit or seed development were observed in both the colour variants. The absence of fruit or seed set can be attributed to very low fertility of the pollen and some incompatibility mechanisms in the flower. The vegetative propagation from leaf was found prominent in both the colour variants under study.
Open Access
Epidemiology and management of black rot of cauliflower in plains of kerala
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Lakshmi Prasanna, S; KAU; Ravi, S
The present study “Epidemiology and management of black rot of cauliflower in plains of Kerala” was taken up at Department of Plant Pathology, College of Horticulture, Vellanikkara and Agriculture Research Station, Mannuthy during 2009-2011 with an aim to study the epidemic factors influencing the incidence, development and severity of black rot caused by Xanthomonas campestris pv. campestris in plains of Kerala and to conduct field studies on its management. The pathogen was isolated from the leaves and curds of cauliflower showing typical symptoms of the disease, on PSPA medium. The colonies of the isolate were yellow in colour, circular, slimy and smooth convex with entire margin. Studies on morphological, cultural and biochemical characters confirmed the bacteria as Xcc. Various types of viz., chlorotic lesion, V shaped lesions, vein blackening; necrosis and vascular discoloration were produced by the pathogen. The symptoms were initially localized and later became systemic and stunting of plants was noticed due to systemic infection. Progression and severity of the disease was studied by inoculating the plants at five days interval starting from 10 days after transplant (DAT) up to 60 DAT. Cauliflower plants of all age group were found to be susceptible to this disease. But, young plants were succumbing to death due to infection. As the age increased there was gradual decrease in the systemic infection. Plant mortality also decreased with the increase in age at which they got infected. Sixteen cauliflower varieties were screened for black rot disease under field conditions. The incidence, calculated as A- value (AUDPC), varied from 0.53 to 12.81. These varieties were grouped in to four categories based on the scale; 0-resistant, 0-3 moderately resistant, 3-5 moderately susceptible and >5 susceptible. Out of sixteen varieties, none was found to be resistant, eight were found to be moderately resistant, two were moderately susceptible and remaining six were susceptible. An attempt was made to formulate a score card for this disease for easy observation and which has a bearing on the yield. The actual area of infection in the leaf at 10, 25 and 40 days old plants were correlated with yield and a equation y=389.061+3.371(10 DAT)-0.986(25 DAT)-2.391(40 DAT) was obtained. Three system of score card were formulated and their relationships with the yield were re-correlated statistically and three additional equations were arrived. The equation two was comparable with the original equation and that score card can be better adopted as it showed 95 per cent similarity to the original, where scale 1 and 3 showed 77.5 and 90.1 per cent similarity respectively. An attempt was made to determine the role of weather parameters on incidence of this disease. The weather factors such as maximum temperature and sunshine hours were positively correlated prevailing to the observation on 9th day and average of 7, 8 and 9 days. Similarly average of 4, 5, 6; 5, 6, 7 and 6, 7, 8 days were positively correlated with only sunshine hours. A partial multiple regression equation is also derived for predicting the disease incidence. Such correlation studies have to be conducted for at least five years consecutively to arrive at a better prediction model. Initial in vitro evaluations were done to identify the chemicals, botanicals and bioagents to be carried to the field. Field trail showed that garlic extract 10 per cent, tetracycline 250 ppm and Pseudomonas fluorescens were best treatments against Xcc.
Open Access
Morphogenesis and reproductive biology of water lily (Nymphaea spp.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Tincy, Tom; KAU; Presanna, Kumari K T
Genus Nymphaea forms a complicated group of aquatic perennials having immense ornamental and medicinal value. Two phenological groups based on flowering viz., diurnals and nocturnals are recognized in this genus. Information on the reproductive biology and developmental features specific to the phenological groups are lacking in this genus. The present study entitled “Morphogenesis and reproductive biology of water lily (Nymphaea spp.)” was taken up in this background in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, during 2013-2015 for elucidating and comparing the reproductive biology and developmental pattern of leaves, flowers and fruits in day as well as night blooming types of Nymphaea. A survey was conducted in the water lily growing tracts of Thrissur district and 12 accessions were collected. Five among these accessions were selected based on blooming time and seed set for further detailed evaluation. Growth and development pattern of leaves and flowers were observed to be uniform in all the accessions. However, the accessions differed in the number of days taken by the leaf and flower bud to reach the water surface and maturity. The rate of elongation of the petiole was significantly and positively correlated with sunshine hours and maximum temperature. There was no significant correlation between pedicel elongation and weather parameters. The leaves in all the accessions evaluated were simple orbicular with subpeltate lamina which was deeply cleft near to the petiole base. However, there was variability in the colour, margin and tip of the lamina. The night bloomers could be easily distinguished by the sinuately dentate margin and thick prominent veins on the abaxial surface of the lamina. Flowers were pedicellate and complete with all the floral whorls in a spiral fashion on the floral axis. Significant variability in both qualitative and quantitative characters were observed among the accessions for floral characters. The night bloomers differed from the day bloomers in having larger flowers with stamens devoid of appendages. Besides, the sepals were observed to have five to six prominent nerves on both sides. The flower opened in the morning and closed in the evening in day blooming types. In night bloomers the flower opening was in the evening hours and closing in the morning hours. The time of opening and closing further varied with the accessions. The process of opening and closing continued for four days and on the fifth day the flower submerged in water. The anther dehiscence started on the second day of flower opening and it proceeded from the outermost whorl to the inner most whorl of the stamens. The dehiscence was hence completed in two days in day bloomers. However, in night bloomers the stamens of all the whorls dehisced simultaneously on the first day of flower opening. The presence of honey dew like secretion in the stigmatic cup indicated the initiation of stigma receptivity in all the accessions irrespective of blooming time. The receptivity started 14 to15 hours before flower opening and was retained for 34 hours even after flower opening in day bloomers. In night bloomers the onset of receptivity was six to nine hours prior to flower opening and remained receptive only for 16 to 18 hours after flower opening. Stingless bee (Trigona irridipennis), honey bee, house flies, weevils and flower beetles were the major insects visiting the flowers. Cross pollination was the rule in all the accessions due to the protogynous nature of the flower. Fruit set was noticed only in two of the day blooming types evaluated. Fruit was a many seeded dehiscent capsule which developed under water. All the floral whorls were persistent in the mature fruit. It took 20 to 25 days for the fruit to mature. Seeds were arillate with an embryo, two fleshy cotyledons and a mucilaginous covering. Despite being a dicot, the germination was initiated by the emergence of coleoptile. Acid scarification as well as leaching treatment enhanced the speed of germination of the seeds. Bulbils served as the propagules in the non seed forming accessions.
Open Access
Genetic evaluation of yield and anthracnose resistance in the segregating generation of three way cross hybrides in chilli
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2013) Vineetha, G; KAU; Manju, P
Chilli (Capsicum annuum L.) is an important spice cum vegetable crop, grown on a commercial scale in India. It is an important constituent of many foods since it adds flavor, colour, vitamin C and pungency, productivity of the crop remains low mostly due to destructive diseases. One of the most dreaded diseases affecting chilli is anthracnose, which is also called dieback and fruit rot. The best way to tackle this disease is to grow resistant varieties. Hence it is essential to identify the sources of anthracnose resistance and study the inheritance of resistance to develop high yielding anthracnose resistant varieties of chilli. The aim of the project was to identify high yielding anthracnose resistant types through evaluation from among the F4 segregating generation of three way cross hybrids in chilli. Eight promising three-way cross hybrids with regard to fruit yield and resistance to anthracnose selected from a previous PG project was used as the material for this study. The eight three way cross hybrids were considered as families and within each family eight progenies were studied. The eight families are given below Family 1 - (Jwalamukhi x Kidangoor local) x Jwalasakhi Family 2 - (Jwalamukhi x Ujwala) x Vellayani Athulya Family 3 - (Jwalasakhi x Vellayani Athulya) x Kidangoor local Family 4 - (Jwalamukhi x Ujwala) x Kidangoor local Family 5 - (Samkranthi local x Vellayani Athulya) x Kidangoor local Family 6 - (Vellayani Athulya x Jwalasakhi) x Samkranthi local Family 7 - (Vellayani Athulya x Ujwala) x Jwalamukhi Family 8 - (Kidangoor local x Ujwala) x Jwalasakhi The investigation was carried out as two separate experiments- Pot culture experiment and Field experiment. Pot culture experiment was laid out in CRD with 8 families and 8 progenies with three replications to score for anthracnose disease by creating disease pressure by artificial inoculation of the plants with the pathogen at 35 DAT and 50 DAT. Six superior progenies from each family with regard to yield and anthracnose resistance were selected for field experiment after eliminating two progenies which exhibited low yield and high anthracnose disease incidence. Viz., progeny 4 and 8, 1 and 4, 4 and 7, 4 and 5, 2 and 5, 2 and 8, 3 and 5, 4 and 6 from families 1, 2, 3,4,5,6,7 and 8 respectively. Family 8 was superior for yield and showed resistance to anthracnose followed by three other families. Progenies which were superior within these families were 8 and 3 in family 8, 6 and 1 in family 5, 8 in family 7 and progeny 3 in family 2. Genetic parameters such as phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance and correlation of 8 families were studied. Fruit yield per plant showed maximum GCV, PCV and genetic advance while heritability percentage was maximum for fruit length and average green fruit weight. Fruit yield per plant showed positive and significant genotypic and phenotypic correlations with average green fruit weight and length of fruit while it showed negative correlation with duration among the families. The field experiment was laid out in Compact Family Block Design, with 8 families and 6 progenies in four replications. Scoring for anthracnose disease was done under natural condition in the field. Among the 8 families, family 8 was highly superior for the important traits such as number of fruits per plant, average green fruit weight, fruit length, fruit girth, fruit yield per plant and was resistant to anthracnose disease. Based on the evaluation of progenies in each family, progeny 1 was significantly superior in family 1, progeny 2 in family 2, progeny 3 in family 3, progeny 4 in family 4, progenies 3 and 4 in family 5, progeny 1 in family 6, progenies 4 and 6 in family 7 and progeny 6 in family 8. Biochemical analysis on chilli revealed that capsaicin and oleoresin were found to be maximum in the above selected progenies in each family which were superior for yield and anthracnose resistance. Progenies which exhibited high capsaicin content were found to exhibit low disease incidence. The study revealed that Kidangoor local x Ujwala x Jwalasakhi (family 8) was the best and was significantly superior followed by Samkranthi local x Vellayani Athulya x Kidangoor local (family 5), Jwalasakhi x Vellayani Athulya x Kidangoor local (family 3), Vellayani Athulya x Jwalasakhi x Samkranthi local (family 6), Vellayani Athulya x Ujwala x Jwalamukhi (family 7) and Jwalamukhi x Ujwala x Vellayani Athulya (family 2). The progenies that were found to be superior within these families will be selected based on yield and yield attributes as well as anthracnose disease resistance for further evaluation of the recombinants in the F5 segregating generation.
Open Access
Genotype X environment interaction in blackgram (Vigna mungo L. Hepper)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Gambhire, Vilas Bhagwat; KAU; Jiji
Blackgram (Vigna mungo (L.) Hepper) is an important short duration pulse crop occupying unique position in Indian agriculture. Its seeds are highly nutritious and used in the preparation of many popular dishes. Pulses are part of the daily diet of vegetarians world over. They are rich in protein (20-30 %) and are an excellent source of dietary fiber, low molecular weight carbohydrates, essential aminoacids, poly unsaturated fatty acids and range of micronutrients. In recent years there has been an increase in consumption of pulses in several developed countries where they are increasingly considered as health food. In Kerala, cultivation of pulses especially black gram as third crop i.e., in summer fallows in paddy growing areas was a common practice by the farmers. However, this trend has come down in the near past due to non availability of labourers for harvesting and low yield of traditional varieties. Raising blackgram in coconut gardens seems as a viable option to increase area of cultivation. In Kerala, high yielding varieties suited to both open and shaded conditions are not available. The study on “Genotype x environment interaction in black gram” was an attempt to identify suitable cultures for cultivation under open condition as a sole crop in rice fallow lands and as an intercrop in coconut garden. Materials used for the study consisted of ten black gram cultures developed by pedigree breeding from four crosses in the stabilized generation at the Department of Plant Breeding and Genetics. The check varieties were TAU-1, T-9, Sumanjana and Syama. The crop was raised under open and shade condition during kharif , rabi and summer seasons of 2013-2014. The plants were raised in plots of five meter square with two replications. All the observations were recorded at harvest except days to flowering. The data was analyzed for stability by Eberhart and Russell’s model as pooled over open condition, pooled over shade condition and pooled over all the six environments. According to Eberhart and Russell’s model of stability a good genotypes is the one having high mean value, non significant bi and S2di value. Stability analysis by Eberhart 13 and Russell’s model pooled over open condition showed that there was no variation between genotypes under three seasons for days to flowering, length of pod and number of seeds per pod. Also none of the genotypes showed stability for protein content. Genotypes were ranked based on stability, yield and major yield contributing characters. The genotypes with least score were T6, T5 and T9. These can be recommended for cultivation under open condition. Stability analysis by Eberhart and Russell’s model pooled over shade condition showed that that there was no variation between genotypes under three seasons for number of seeds per pod. None of the genotype was stable for protein content. Ranking of genotypes showed that genotypes T3, T5, T6 and T10 can be recommended for cultivation as an inter crop in coconut garden. Estimation of stability by Eberhart and Russell’s model pooled over six environments showed that there was variation between genotypes under the environments for all the traits studied. Genotypes were ranked based on stability, yield and major yield contributing characters. The genotypes with least score were T6, T5 and T3. These can be recommended for cultivation under both the conditions. Based on G x E analysis done by AMMI model also genotypes T5, T6 and T 3 were identified as suitable for planting under the six environments. The identified genotypes suitable for each condition that is genotypes T3, T5, T6,T9 and T10 has be evaluated in large plots to confirm the results and the quality of these genotypes has to be assessed for developing as variety suitable for open condition and intercropping.
Open Access
Analysis of bean characters in cocoa (Theobroma cacao L.) hybrids bred for bold beans
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Rubeena, M; KAU; Presannakumari, K T
Cocoa is a tropical tree crop cultivated for its beans which form the main source of chocolate. Many of the cocoa varieties cultivated by the farmers, even though high yielders, are having small beans. However, the standard for cocoa bean in the international market is one gram or above. The size of bean is significantly influenced by various environmental conditions especially temperature, prevailing during the pod formation stage. Hence, the cocoa beans produced in summer months may fail to keep the international standards. To overcome this, it is necessary to evolve varieties with large beans of more than 2g so that even if reduction occurs during summer months the beans will have enough size to meet the international standards. The present study which forms part of an ongoing project at Cocoa Research Centre (CRC), KAU, Vellanikkara was hence, taken up during 2012-14 to evaluate the inheritance of various bean characters and to assess the threshold bean size as well as the heterotic effect for various bean characters. Forty hybrid progenies derived from four crosses involving five parents, which are in full bearing stage and maintained at CRC, Vellanikkara formed the material for the study. These hybrids were subjected to morphological and biochemical evaluation along with their parents. The morphological evaluation based on eight qualitative and 14 quantitative characters was done using the descriptor developed by Bekele and Butler (2000). Fat and polyphenol contents were estimated following standard procedures for biochemical characterization. Variability was observed among the hybrid progenies for all the qualitative characters evaluated. Variations expressed by the hybrid progenies in terms of pod and bean quantitative characters were also significant, indicating the heterogeneity among them. Analysis of bean characters revealed that the hybrids 13.7, 16.8, 14.6 and 12.5 expressed higher values with respect to wet weight of unpeeled bean (460g), length of peeled bean (17.78mm), breadth of peeled bean (10.81mm) and peeling ratio 82.4% respectively. The highest wet weight of peeled bean (1.78g) was recorded by hybrids 12.5 and 12.6. The dry weight of peeled bean (1.31g) and thickness of peeled bean (4.98mm) were the highest in hybrid 12.6. The fat content ranged from 33.3% in hybrid 7.8 to 58.5% in hybrid 10.6 and polyphenol content ranged from 0.15% in hybrid 16.8 to 0.56 % in hybrid 5.7. Among the pod and bean characters evaluated wet weight of peeled bean exhibited high GCV (510%), high heritability and high genetic gain (1163%). The bean characters varied significantly over seasons in hybrids as well as parents. Relatively higher bean weights were observed in September- November period harvests in contrast to the lower bean weights during June to August period. Assessment of performance of hybrids based on year round observation on bean characters revealed that the major factors contributing significantly to boldness of bean were weight, breadth and thickness of beans. Based on these parameters a descriptor was developed confirming the international standards, for deciding the threshold bean size. The descriptor scales were prescribed based on the best subset values in the post hoc tests. Hybrids 12.6, 13.7 and 14.6 satisfied the developed scales Significant positive heterotic effect (average heterosis as well as heterobeltiosis) for various bean characters was expressed by hybrids 13.7 and 12.6. Among the hybrid progenies evaluated hybrid 13.7 was found to be a desirable one with low pod index value (PI value), high pod breadth, pod weight and wet weight of unpeeled bean coupled with significant positive heterotic effect for various bean character followed by hybrids 12.6, 16.5 and 14.6.

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