Evaluation of inbred lines derived from commercial hybrids and their utilization in developing high yielding field corn (Zea mays L.) hybrids

Genetic enhancement and identification of genetically broad-based inbred lines for the development of new hybrids is the pre-requisite for the heterosis breeding. Newly derived 118 inbred lines were evaluated for their morpho-physiological characters in order to identify best suitable male and female parental lines. Total 10 best inbred lines were selected after thorough evaluation of 16 stable inbred lines, identified from the pool of 118 inbred lines. These inbred lines were crossed in line × tester manner, considering three inbred lines as male andrest as female, based on the Specific Combining Ability and General Combining Ability. Hybrids thus obtained were evaluated in two diverse agroclimatic situations and best heterotic hybrids were selected based on their standard heterosis and rank obtained in Duncan's Multiple Range Test analysis. Single location ANOVA for inbred lines and combined ANOVA for hybrids showed that selected inbreds and hybrids were significantly differing from each other. Since, there exists a Genotype × Environment interaction among hybrids, PCA also taken into consideration for giving weight as classification variable for the hybrids. Further, multi-location evaluation of these hybrids is proposed to identify stable hybrids suitable for large scale commercialization

Studies on Harvest Index in Soybean

According to Vogel et 01. (1963) the r.i.ght approach to increase the seed yield is the improvement in total biological yield and/or harvest index. Further, harvest index is a highly conservative and stable character (Spaeth et 01; 1984, Mercellos, 1987) and accounts for 95% variation in seed yield alongwith growth rate (Takeda et 01., 1979). These factors empha"ize the importance of harvest index in identifying the most efficient genotypes with superior biological and seed yielding abilities (Sharma et af., 1987). But the study of genetic architecture of harvest index is essential before embarking upon selection based 011 it. In the present study heterosis, combining abil ity and gene effects for harvest index were investigated..........

Genetic variability, combining ability and molecular diversity-based parental line selection for heterosis breeding in field corn (Zea mays L.)

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGBackground: The demand of maize crop is increasing day by day, hence to reduce the production and demand gap, there is a need to extract the high yielding parental lines to improve per se yield of the hybrids, which could help to enhance the productivity in maize crops. Methods and results: The present investigation was carried out to select the best medium maturing inbred lines, among a set of 118 inbred lines. Based on the Duncan multiple range test, out of 118 lines, 16 inbred lines were selected on the basis of its high yield per se and flowering time. The molecular diversity was carried out using SSR markers linked to heterotic QTL and up on diversity analysis it classified selected genotypes in to three distinct groups. Among the selected inbred lines, a wider genetic variability and molecular diversity were observed. A total of 39 test crosses were generated after classifying 16 inbred lines in to three testers and thirteen lines (based on per se grain yield and molecular diversity) and crossing them in line × tester manner. Conclusion: Combining ability analysis of these parental lines showed that female parents, PML 109, PML 110, PML 111, PML 114 and PML 116 showed additive effect for KRN and grain yield, whereas male parents, PML 46, and PML 93 showed epistatic effect for KRN and PML 102 showed epistatic effect for grain yield. The generated information in the present investigation may be exploited for heterosis breeding in filed corn. Key messages To tackle the balanced dietary requirement of Indian population; we focused to enhance the productivity of maize hybrids using genetically broad based, elite, diverse inbred lines. Combination of selection criterion, not only augment the productivity but also improves the quality of hybrid/s

Estimation of heterosis for grain yield and quality traits in sweet corn (Zea mays var. sacharata L.)

The study was carried out to estimate heterosis for yield and biochemical quality traits in sweet corn (Zea mays var. sacharata) crosses. Forty five hybrids using diallel mating design excluding reciprocals were generated. These hybrids along with their ten parents and one standard check (Madhuri) were grown at IARI, New Delhi during kharif-2008 in randomized block design (RBD). Estimation of heterosis over standard check (HSC) ‘Madhuri’, mid-parent (HMP), and better parent (HBP) was calculated. The significant heterosis over standard check for grain yield was found in five crosses, and for sugar content in twelve crosses out of forty five. The HMP for grain yield was found in eighteen crosses and for sugar content in nine crosses. The HMP for grain yield and sugar content was found in IPSA-6134 × IPSA-6141, IPSA-6135 × IPSA-6136, and IPSA-6141 × IPSA-6142. One cross IPSA-6137 × IPSA-6139 showed HMP for protein content and grain yield. One cross IPSA-6136 × IPSA-6139 showed HMP for sugar content and protein content. The HBP was observed in IPSA-6135 × IPSA-6136, IPSA-6136 × IPSA-6139, IPSA-6138 × IPSA-6141, IPSA-6139 × IPSA-6140 and IPSA-6140 × IPSA-6141 for sugar content and IPSA-6134 × IPSA-6137, IPSA-6134 × IPSA-6141, IPSA-6134 × IPSA-6142, IPSA-6135 × IPSA-6139, IPSA-6140 × IPSA-6142, and IPSA-6141 × IPSA-6142 for grain yield. Two crosses IPSA-6135 × IPSA-6136 and IPSA-6141 × IPSA-6142 have the HBP for grain yield and sugar content. One cross IPSA 6137 × IPSA 6139 showed the HBP for protein and grain yield

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Not AvailableThe study was carried out to estimate heterosis for yield and biochemical quality traits in sweet corn (Zea mays var. sacharata) crosses. Forty five hybrids using diallel mating design excluding reciprocals were generated. These hybrids along with their ten parents and one standard check (Madhuri) were grown at IARI, New Delhi during kharif-2008 in randomized block design (RBD). Estimation of heterosis over standard check (HSC) ‘Madhuri’, mid-parent (HMP), and better parent (HBP) was calculated. The significant heterosis over standard check for grain yield was found in five crosses, and for sugar content in twelve crosses out of forty five. The HMP for grain yield was found in eighteen crosses and for sugar content in nine crosses. The HMP for grain yield and sugar content was found in IPSA-6134 × IPSA-6141, IPSA-6135 × IPSA-6136, and IPSA-6141 × IPSA-6142. One cross IPSA-6137 × IPSA-6139 showed HMP for protein content and grain yield. One cross IPSA-6136 × IPSA-6139 showed HMP for sugar content and protein content. The HBP was observed in IPSA6135 × IPSA-6136, IPSA-6136 × IPSA-6139, IPSA-6138 × IPSA-6141, IPSA-6139 × IPSA-6140 and IPSA6140 × IPSA-6141 for sugar content and IPSA-6134 × IPSA-6137, IPSA-6134 × IPSA-6141, IPSA-6134 × IPSA-6142, IPSA-6135 × IPSA-6139, IPSA-6140 × IPSA-6142, and IPSA-6141 × IPSA-6142 for grain yield. Two crosses IPSA-6135 × IPSA-6136 and IPSA-6141 × IPSA-6142 have the HBP for grain yield and sugar content. One cross IPSA 6137 × IPSA 6139 showed the HBP for protein and grain yield.Not Availabl

Genetic variability and correlation among yield and quality traits in sweet corn

The 45 hybrids generated by half diallel mating design using ten inbred lines of sweet corn were evaluated at IARI, New Delhi during kharif-2008. There were significant differences with respect to all the studied yield and biochemical attributes. High genotypic and phenotypic variance were recorded by plant height, cob placement height, grain rows cob-1, hundred grains weight, grain yield and starch content. The difference between genotypic coefficient of variation and phenotypic coefficient of variation was less for all the traits, indicating that improvement is possible through phenotypic selection. High heritability coupled with high genetic advance for cobs plant-1, reducing, non-reducing and total sugars and oil contents, suggests that selection may be effective for these traits. The yield attributing traits showed the high heritability, but low genetic advance indicating non-additive gene action. High genotypic positive correlation was observed between flowering and maturity days, indicates that selection for earliness can be done on the basis of these traits simultaneously. Cob length and grains row-1 showed the positive correlation. There was no strong correlation between yield attributes and biochemical parameters. There was positive correlation between; non-reducing sugar - total sugars, non-reducing sugar - oil content and total sugars - oil content which indicates that sugar content and oil content both can be increased simultaneously by the selection programme

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Not AvailableAmong the specialty corns, sweet corn has gaining its importance in urban areas due to its taste and other uses for human consumption. But, non-availability of high yielding sweet corn varieties, the green ears of flint-grained local varieties which are relatively sweeter and taste better are also consumed as roasted ears. Thus, enhancement of kernel sugar content, in addition to higher productivity will be a desirable attribute in facilitating diversified utilization through human consumption of fresh kernel as well as processed food.Not Availabl