An integrated approach of breeding and maintaining an elite cultivar of snap bean

This study is an attempt to describe a functional breeding and maintaining program of intraselection in a traditional snap bean (Phaseolus vulgaris L. ) cultivar. The program was applied in three stages. The first thing examin ed was the existing genetic variability of source material for earliness an d pod yield potential. Single-plant Frequency distributions with positive s kewness for earliness showed that the frequency of unfavorable alleles was high. For total pod yield, distribution was found normal. Thus, the end-tar get should be selection for early maturity, keeping, and stabilizing high y ield. The seed shape uniformity was added as third criterion of selection. Secondly, combined pedigree intraselection, based on widely spaced single-p lant performance, for the prementioned traits was applied for three success ive generations. The evaluation of the third-generation families revealed p rogenies with high yield, earliness, and stability of performance. Thirdly, the end-product of the program applied was to restore or even improve the cultivar. The evaluation of improved selections of fourth-generation famili es and of the source material, at dense stand, showed that all families wer e the only ones producing high and stable early fresh pod harvest, even 53 d after planting (53.25-80 g/plant, compared with 0 g/plant of the control) . The total pod yield of all the families was 219 to 276% superior compared with source material. Conclusively, the widely spaced single-plant combine d pedigree intraselection was proved reliable and effective in restoring or even improving the local cultivar of snap bean according to update demands .