To identify an efficient pollen source for maize mediated system of chromosome elimination, wheat genotypes (10 F1s) were pollinated with eight diverse Himalayan maize genotypes. Among these, two were composite varieties Early Composite (Check) and Bajaura Makka (L 201) and rest six were locally grown traditional open pollinated maize varieties collected from diverse regions of North-west Himalaya. The data were recorded for three haploid induction parameters viz. pseudo seed formation, embryo formation and regeneration. In most of the crosses, haploid embryos were produced, asserting the potential of wheat × maize system as a genotype non-specific system as compared to androgenesis and bulbosum technique, where the genotype specificity limits the development of haploid plants. Frequencies of all the three haploid induction parameters in different crosses of wheat × maize clearly indicated that both wheat and maize genotypes were behaving differently for different crosses. The line × tester analysis also revealed significant influence of crosses, wheat, maize and their interaction on all the three haploid induction parameters. The results obtained suggest association of both additive and dominance gene action with all the haploid induction parameters. Over all proportional contribution of tester for embryo formation and regeneration parameters was found to be more, followed by line × tester interaction. On the basis of haploid formation efficiency (HFE) as well as general combining ability (GCA), Bajaura Makka has emerged to be the best general combiner among maize genotypes and also superior to the earlier identified variety, Early Composite. Also, HPW 155 × VL 852 and HPW 155 × HPW 211 were the top general combiners among wheat genotypes. Correlation between various haploid induction parameters revealed negative correlation between pseudo seed formation and embryo formation whereas embryo formation and regeneration were found to be significantly positively correlated; however the magnitude of correlation was not very high.
Authors:Vijay Rana, Dhirendra Singh, R. Dhiman, and H.K. Chaudhary
Thirty diverse elite Indian wheat genotypes varying in their yield performance and drought tolerance were evaluated to examine differences for some drought tolerance characters and to determine relationship between these characters. Genotypes differed in their response for grain yield, days to heading, excised-leaf water loss and relative water content under both conditions over years. Under irrigated conditions differences in the genotypes for water retention traits were not clear. The varieties HPW251, Hindi 62, HPW184, VL 892 and VL 907 showed a good combination of drought resistance, water retention and high grain yield, whereas C 306, VL 421 and NI 5439 had high grain yield only under drought stress conditions and showed better water retention in the leaves. These genotypes may be used for exploitation of drought tolerance in wheat breeding programmes. Drought response index (DRI) appeared to be an important trait as the genotypes having high DRI values also had high grain yield, high water retention and low score of drought susceptibility index (DSI) under drought stress.