Gamete Selection for Simultaneous Improvement of Multiple Traits in Common Bean
- Shree P. Singh
A successful crop improvement program depends upon the ability of breeders and geneticists to effectively and efficiently create, identify, and select recombinant genotypes with a maximum number of desirable traits in the shortest time possible. Therefore, alternative methods of gene recombination and selection need to be studied. My objective is to describe a method of gamete selection for simultaneous improvement of multiple traits in common bean (Phaseolus vulgaris L.). Gametes election is based on the premise that (i) multiple-parent crosses are required for simultaneous improvement of multiple traits; (ii) the male parents of the final crosses are heterozygous and hence heterogametic;( iii) each zygotic seed is a product of a separate, independent fertilization event; (iv) further chromosomal and genic recombination is limited to genetic material contained within each initial zygote; and (v) early generation (i.e., F1, F2, F3, and F4) testing and selection are an essential part of the methodology. Thus, eventually, plant-to-plant pairwise pollination is done between the elite female and beterogametic male parents (selected a priori for desirable dominant and codominant alleles), followed by harvesting and sowing resultant hybrid seeds from each hybridization event in separate plots to obtain F1-derived families. These are subsequently evaluated in separate, replicated complementary nurseries for seed yield and other agronomic traits, including reactions to diseases and insects, low soil fertility, and/or drought. This permits identifying promising populations and families within populations possessing genes for multiple desirable traits in early generations for further evaluation, selection, and development of improved cultivars.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1994.