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GENETIC DIVERGENCE, COMBINING ABILITY AND STABILITY FOR COB YIELD AND OTHER TRAITS IN BABY CORN (Zea mays L.)

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(GENETIC DIVERGENCE, COMBINING ABILITY AND STABILITY FOR COB YIELD AND OTHER TRAITS IN BABY CORN (Zea mays L.))

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2015
SUDHEER KUMAR, S
PROFESSOR JAYSHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
D9833;

The present investigation “genetic divergence, combining ability and stability for cob yield and other traits in baby corn (Zea mays L.)” was undertaken to identify the diverse parents in maize and study the combining ability, nature of gene action, heterosis, genetic parameters, character association, G X E interaction and stability of experimental hybrids for yield and other traits. During rabi 2011-12 eighty genotypes were evaluated for genetic diversity at College Farm, College of Agriculture, Rajendranagar, Hyderabad. The analysis of variance revealed significant differences among the genotypes for all the characters studied except moisture content. Based on Mahalanobis D2 analysis the 80 genotypes were grouped into eight clusters. Cluster I was the largest having 38 genotypes followed by cluster III with 26 genotypes, cluster V with 7 genotypes, cluster VI with 5 genotypes and the clusters II, IV, VII and VIII had one genotype each. From this clusters 25 parents were selected and used in hybridization programme. Twenty five divergent parents were crossed in Line x Tester mating design by involving three testers during kharif 2012 at Maize research center, ARI, Rajendranagar, Hyderabad. The resulting 75 crosses along with parents and two standard checks viz., DMR-1142 and DMR-1144 were evaluated in Randomized Block Design replicated thrice during rabi 2012-13 at three locations viz., in Central Telangana Zone (Rajendranagar, Ranga Reddy), Northern Telangana Zone (Jagityal, Karimnagar) and Central Telangana Zone (Kampasagar, Nalgonda). The pooled analysis of variance for combining ability revealed significant differences due to environments, parents, hybrids and various interactions indicating the existence of wider variability in the material studied. The ratios of GCA/SCA variances revealed that non additive gene action was predominant in the inheritance of all the characters. Combining ability analysis revealed that among the parents, BML-5222, QPM-69-2, BML-5121, BML-5212 and BML-5207 were good general combiners for earliness viz., days to 50 per cent tasseling and days to 50 percent silking. Parents, BML-5212, BML-5121, BML-5118-3, QPM-57-1, BML-5161 and CM-131(Tester) recorded significant positive gca effects for cob yield per plant and these inbreds may be utilized in the development of hybrids, synthetics or composites. The hybrids, QPM-62 X BML-6, CM-201 X BML-6 and BML-5342 X CM-131 were found to be good specific combiners for earliness, While the hybrids BML-5118-3 X BML-6, BML-5121 X BML-6, BML-5212 X BML-13, BML-5161 X BML-6 and QPM-62 X BML-13 which recorded positively significant sca effects for cob yield per plant are considered as good specific combiners. Therefore these hybrids may be recommended for heterosis breeding. In pooled analysis high narrow sense heritability estimates were recorded in plant height, green fodder yield, cob yield, baby corn length, ear height and cob weight. Thus these traits are predominantly under the control of additive gene action and hence, these characters can be improved by selection in the development of new inbred lines. Estimates of heterobeltiosis and standard heterosis were variable among crosses in desirable direction and some of them turned out to be best specific crosses. Heterosis for cob yield per plant is mainly because of simultaneous manifestation of heterosis for yield component traits. The highest standard heterosis for cob yield per plant was recorded for hybrids BML-5121 X CM-131, BML-5212 X BML-13, BML-5121 X BML-6, BML-5212 X CM-131 and BML-5121 X BML-13 along with per se performance, heterobeltiosis. These hybrids may be further tested in multilocation evaluation before releasing them for commercial cultivation. Results of stability analysis revealed that ten hybrids viz., BML-5121 X BML-6, BML-5161 X BML-6, QPM-69-2 X CM-131, BML-5016 X CM-131, BML-5219 X CM-131, BML-5204-5-2-1 X CM-131, CM-119 X BML-13, BML-5347-2 X CM-131 and QPM-57-1 X CM-131 are identified as stable and best performing hybrids for cob yield per plant and other traits hence, suitable for wider environments. Based on overall performance the best hybrid identified was BML-5121 X BML-6 with highest cob yield per plant of 27.93 g, with high sca effect (1.95), significant standard heterosis (77.32 %) and significant heterobeltiosis (78.33 %) over the check DMR-1142. This hybrid was stable over locations for cob yield per plant, days to 50 per cent tasseling, days to 50 per cent silking, plant height, ear height, baby corn length, baby corn girth, cob weight and cob yield per hectare. The next best hybrid was BML-5161 X BML-6 with a cob yield per plant of 20.39 g with significant sca effect (1.42), significant standard heterosis over DMR-1142 (29.43%) and significant heterobeltiosis (39.53%). This hybrid was stable over locations for cob yield per plant, days to 50 per cent tasseling, days to 50 per cent silking, plant height, baby corn length, baby corn girth, cob yield per hectare, green fodder yield and TSS. The correlation and path coefficient analysis, emphasized the need for selection based on plant type with greater number of cobs per plant, cob weight, corn length, days to 50 per cent silking, plant height, corn girth. Since these were found to be the important direct contributors for cob yield per plant. Keeping in view of the above facts, by considering all factors like per se performance, sca effect, standard heterosis, heterobeltiosis and stability, the most promising hybrids identified were BML-5121 X BML-6, and BML-5161 X BML-6.These hybrids may be further tested over locations, seasons, years before recommending for commercial release.

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