Backcrosses were attempted of F 1 hybrids of spring wheat genotypes (HS 375 and C 306) and winter wheat genotypes (Saptdhara and Tyari) with the Indian rye (Secale cereale L.) landrace ÔLahaul LocalÕ. Intergeneric hybridizations using pollen of maize and Imperata cylindrica (2n = 20), a wild and weedy species, were conducted in the wheat-rye-derived backcross BC 1 F 1 and BC 1 F 2 generations to study the relative efficiency of the two chromosome elimination approaches in the induction of haploid plants. Although seed formation was similar with both pollen sources, the relative frequency of embryo-carrying seeds ranged from 8% to 30% with I. cylindrica, whereas with maize, no embryo-carrying seed was obtained. Comparisons of induction of haploid plants in the wheat-rye backcross derivatives showed that the wheat · I. cylindrica system was superior to the wheat · maize system and was also cost effective as it shares the flowering season with wheat in sub-temperate conditions.

Bread wheat (Triticum aestivum L.) is a major food grain in India next to rice. Therefore, improving yield and yield stability is the primary objective of wheat breeding programmes in this country. The eleven wheat genotypes were evaluated under eight locations representing typical rainfed conditions of the North Hill Zone. The study based on AMMI and GGE biplot analysis methods to highlight the G×E interaction in multi-location trials and stratification of genotypes as per their adaptability for rainfed conditions of the northern hill zone. Combined ANOVA analysis showed highly significant differences (p<0.001) of 11 genotypes under rainfed conditions of North Hill Zone. Highly significant environments, genotypes and G×E interaction explained 81.4%, 2.3% and 15.7% of the total sum of squares, respectively (Table 2). The significant GE interaction sum of squares is further portioned into seven significant Interaction Principal Components Axes (IPCAs) and a residual term. The first four interaction principal component analysis (IPCA1, IPCA2, IPCA3 and IPCA4) explained 33.6%, 28.1%, 19.5% and 10.0% of the G×E interaction variation, respectively. Accordingly AMMI analysis for stability, genotypes G15, G3, G8, and G1 were shown to have a higher stability for yield than other genotypes. The GGE biplot analysis shown that the genotypes G10, G5, G7 and G1 were corner genotypes and suited to particular environments.

Vitamin A deficiency (VAD) is a global health problem; many people around the world, especially children and pregnant women, are VAD deficient or insufficient. Maize is known as an important source of provitamin A for humans. Hence, enhancement of provitamin A carotenoids (pVAC) in maize varieties through breeding or biofortification is a good option for alleviating VAD in developing countries, especially India. So far, numerous maize hybrids have been developed in India. Among them, CO6, derived from UMI1200 × UMI1230, is a popular maize hybrid and adapted to different agro-climatic zones of India, especially Tamil Nadu, a southern state of India. However, CO6 is deficient for pVAC carotenoid β-carotene. Thus, the objectives of this study were to increase the β-carotene concentration in UMI1200 and UMI1230 and generate the β-carotene enriched hybrids through marker-assisted backcross breeding (MABB). For this purpose, the maize genotype HP467-15 was used as the donor for transferring the β-carotene gene, crtRB1 , into UMI1200 and UMI1230. In the MABB scheme, we used one gene-specific marker ( crtRB1 3′TE) and 214 simples sequence repeat (SSR) markers for foreground and background selection, respectively. As a result, six improved lines with recurrent parent genome recovery (RPGR) ranging from 90.24 to 92.42%, along with good agronomic performance, were generated. The β-carotene concentration of the improved lines ranged from 7.056 to 9.232 μg/g. Furthermore, five hybrid combinations were generated using improved lines and evaluated in a comparative yield trial (CYT) and multi-location trials (MLT) along with the original hybrid CO6 and commercial hybrids. It was revealed that ACM-M13-002 was a superior hybrid with a 7.3-fold increase in β-carotene concentration and with a comparable yield to CO6. In summary, the improved maize inbreds can be used as possible donors for the development of β-carotene-rich cultivars in maize breeding programs and the β-carotene enriched hybrid developed in this study will hold great promise for food and nutritional security.

No abstract

Analysis of genetic variability, heritability, correlation, path analysis, principal component and cluster analysis was carried for 25 blackgram genotypes grown in the foothills of Manipur. The results showed that phenotypic coefficients of variability recorded were higher than the genotypic coefficients of variability, irrespective of traits, demonstrating the effect of environment thereon. The present study revealed that the heritability (bs) estimates were maximum (>50%) for the traits such as days taken to attain the 50% flowering, number of clusters/plant, number of pods/plant and 100 seed weight. The correlation and path analysis proved the selection of the yield attributes in blackgram based on the characters, viz., number of pods/plant and number of cluster/plants. The first three principal components, having the Eigen values more than 1, contributed 84.52% towards variability among the 25 genotypes screened for quantitative traits. Based on the average linkage, 25 genotypes were grouped into five (5) clusters.