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Birsa Agricultural University, Ranchi

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Subject: Plant Breeding × Author: Nitish De × End date: 1996 × Start date: 1996 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Genetic Studies of Some Quantitative Characters in Maize (zea mays L.)
    (Birsa Agricultural University, Ranchi, 1996) Nitish De; D.K.Ganguli
    The present investigation entitled "Genetic studies of some quantitative characters in mize (Zen mys L.)" was carried out with a set of eleven mize genotypes which were crossed in all possible combinations without reciprocals. The fifty five crosses along with their parents and two checks were evaluated in a randomized complete block design with three replications during kharif 1994 to study variability, heterosis, combining ability and gene action for eleven quantitative plant characters, and also the yield prediction of double cross and synthetics that could be constituted for future utilization. The observation data over replication were utilized in analysing various genetic parameters. Estimmtes of combining ability for various characters ware done following dinllel (11 x 11) after Griffing (19560) as well an by line x tester (B lines x 3 testers) after Kempthorne (1957) taking some eleven genotypes in the two CASOS. Highly significant differences among the parents, and among the crosses were observed for all the characters. The mean values of the crosses were more than the parental for all the characters except for days to 50 per cent silk. mean Grain yield per plant, car height, number of kernels per car, number of kernels per row and ear length showed considerable phenotypic and genotypic coefficient of variation. The heritability estimates in broad sense for all the characters were higher in parents than the crosses. No character was found to have high heritability estimate together with high genetic advance. The extent of heterosis over mid-parent, better parent and two checks (Ganga Safed-2 and Suwan) for different characters varied considerably. Most of the crosses were found to give negative heterosis over the check varieties in mjority of the characters, however in case of days to 50 per cent silk, days to maturity, car girth and 100-kernel weight most of the crosses showed positive standard heterosis. Highest and significant positive standard heterosis over better check (Susan) for grain yield was observed in the cross BAU-8312 x CM-4385 (24.49 %). Heterosis for grain yield found to be associated with simultaneous heterosis in other component characters which differed in different crosses. However, 100-kernel weight, plant height and ear girth were the three commonest characters associated with heterosis for yield. The combining ability studies indicated the importance additive and non-additive gene actions in the expression characters, although The non-additive. gene action predominated, and the presence of over-dominance was observed in all the characters under both the mting designs except for days. to 50 per cent silk in diallel only.. The genotype BAU-SW/82 was the best general combiner for grain yield followed by BAU-8312, CM-4385 and BAU-W.Pool. The lines which were superior combiners for grain yield were also superior cabiners for one or more yield components. The crosses viz., BAU-8312 x CM-4385, CM-4357 x CM-600, CM-600 x BAU-W.Pool, BAU-SW/82 x CML-4386 and BAU-SW/82 x CML-4385 were the best specific cross combinations for grain yield per plant. under diallel analysis while CM-der* CM-600, CM-4373 x CM-600 and CM-4386 x BAU-W.Pool were best, line x tester analysis. CM-4357 x CM-600 being common one. Crosses showing high sca for grain yield also exhibited high sca for some component characters. In the comparative study between two mating designs the best general combiner for grain yield (BAU-SW/82) was the same. The estimates of various genetic components were also more or less similar in most of the characters under both diallel and line x tester analyses. The best specific cross combinations for yield and other characters. slightly differed in two methods of analyses. The per se performance of parents were found to be correlated with the gca effects for all the characters except for ear girth under diallel analysis whereas no such relation was found in line x tester analysis except for days to 50 per cent silk. However, the per se performance of the crosses showed parallel relationship with the sca effects for all the characters unler both the methods of unlysos. The best predicted double cross hybrid was (BAU-SW/82 x BAU-8312) x (CM-4385 x CL-4386) with an estimated yield of 61.69 q/ha and was 9.81 per cent higher than the better check Suwan (56.18 q/ha). Single cross hybrids gave better yield performance over the predicted double cross hybrids and synthetics. Top single crossos for grain yield do not constitute to give prodicted top double. cross yield. The predicted yield of all the syntheties were found lower than the check Suwan.