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20132
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Subject: Plant Breeding and Genetics ×

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    ThesisItemOpen Access
    Studies on genetic diversity in rice (Oryza Sativa L.)
    (Department of Plant Breeding & Genetics, BAU, Sabour, 2013) Singh, Parmeshwar Kumar
    Rice (Oryza sativa L.) is one of the staple cereal crops of the world and it is one of the main source of carbohydrate for nearly one half of the world population .Genetic diversity is the basic requirement for making progress in crop breeding. Inclusion of genetically divergent parents of any breeding programme is essential to create new genetic stocks. Genetic diversity is the most important tool in hands of the plant breeder in choosing the right type of parents for hybridization programme. The divergence can be studied by technique using D2 statistics developed by Mahalanobis (1936).It is based on multivariate analysis and grouped into various cluster as given by Rao (1952).This is considered as the most effective method for qualifying the degree of genetic diversity among the genotypes including in the study. From the experimental result it may be concluded that GK.HEMA recorded to be the best performer for grain yield/hill, harvest index, test weight, number of spikelet/panicle, flag leaf width, likes wise ORJ 1024 for number of tillers/hill, flag leaf length and panicle length, AD 08142 for number of effective tillers/hill, number of fertile spikelets/panicle and spikelets fertility % and OR 2322-25 for grain l/b ratio and grain yield (t/ha). The characters with high heritability coupled with genetic advance as per cent of mean were, number of spikelet/panicle, number of fertile spikelet/panicle, straw yield/hill, biological yield/hill, plant height, days to 50 % flowering, spikelet fertility percentage should be given top priority during selection of the genetically divergent parent for future utilization as parents in breeding programme. The genotype of Cluster-IV (OR 2322-25), Cluster-VI (PAU 3835-12-1-1-2), Cluster IX (AD 08142) and Cluster II (GK.HEMA) having desired mean value for characters like days to 50 % flowering, plant height, grain l/b ratio, grain yield, number of spikelets/panicle, test weight, grain yield/hill were more divergent from genotypes of Cluster-V (RP 5341 PSBRC 68 & ORJ 1024) having desired mean for straw yield, biological yield, number of tiller/hill, flag leaf length, panicle length. Thus, these genotypes may be used in future hybridization programme. To achieve the desired segregants for mid duration irrigated rice variety with higher yield. As the results was based on one year data, further, experimentation is required to corroborate the results.
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    ThesisItemOpen Access
    Heterosis and combining ability study for high yield in maize (Zea mays L.) hybrids
    (Deptt. of Plant Breeeding & Genetics, BAU, Sabour, 2013) Kanchan, Miss
    The present study was conducted at the field of maize section, Bihar Agricultural University, Sabour, Bhagalpur. The investigation was based on per se performance, combining ability and heterosis of exotic lines and their single cross hybrids with a view to know the performance of the parents and F1(crosses). The Line x Tester analysis was carried out involving 9 exotic lines and 4 testers (Tulbulia local, BML6, BML7, Suwan). Each line was crossed on to each of the tester during kharif 2012. The evaluation trial of crosses and parents was conducted during rabi 2012-13. The experimental material consisted of 36 F1’s and two checks, namely DHM-117 and Shaktiman-3. The trial was sown on the 22nd November, 2012 in randomized block design with 3 replications. Data was recorded on 10 quantitative characters including reproductive traits, grain yield and yield attributing traits. The estimates of variance component revealed that variance due to SCA was more pronounced than variance due to GCA for all the characters under study, indicating the importance of non-additive type of gene action for the expression for those characters. The GCA effect for grain yield revealed that line L2 was the best general combiner followed by L6, L4, L3 and L7. Among 36 crosses, the crosses, L4 x T4, L2 x T2 and L6 x T2 showed more than 15% heterosis for grain yield. Thus, it was concluded that the cross L4 x T4, L2 x T2 and L6 x T2 were the best crosses and found suitable for higher yield on the basis of mean performance, SCA effect and heterotic effect for grain yield and other yield attributing characters.