to compensate for the declining native variability by deliberate maintenance.
This study is an attempt to describe a functional breeding andMajor breeding objectives in snap bean (Phaseolus maintaining program of intraselection in a traditional snap bean vulgaris L.) concern the development of cultivars com-(Phaseolus vulgaris L.) cultivar. The program was applied in three bining high productivity, stable yields, earliness, pest stages. The first thing examined was the existing genetic variability of source material for earliness and pod yield potential. Single-plant and disease resistance, tolerance to environmental frequency distributions with positive skewness for earliness showed stresses, and desirable agronomic-horticultural attrithat the frequency of unfavorable alleles was high. For total pod butes (Silbernagel, 1986; Singh, 1992). The achievement yield, distribution was found normal. Thus, the end-target should be of such objectives should take into account the cropping selection for early maturity, keeping, and stabilizing high yield. The systems, the ecological conditions, and the preference seed shape uniformity was added as third criterion of selection. Secof consumers in the target areas. In temperate areas ondly, combined pedigree intraselection, based on widely spaced sinof monocropping and intensive cultivation, mechanical gle-plant performance, for the prementioned traits was applied for cultivation, and industrial processing of the final product three successive generations. The evaluation of the third-generation have directed efforts to breed varieties with determinate families revealed progenies with high yield, earliness, and stability of bush type, short duration, concentrated pod maturation, performance. Thirdly, the end-product of the program applied was and uniformity in plant height, seed shape, and size. to restore or even improve the cultivar. The evaluation of improved selections of fourth-generation families and of the source material, Much of the genetic improvement of snap bean has at dense stand, showed that all families were the only ones producing been achieved through the selection of varieties by high and stable early fresh pod harvest, even 53 d after planting applying conventional breeding techniques of self-polli-(53.25-80 g/plant, compared with 0 g/plant of the control). The total nated crops (Singh, 1992) such as bulk, pedigree, backpod yield of all the families was 219 to 276% superior compared cross, and their modifications (Brim, 1966) such as the with source material. Conclusively, the widely spaced single-plant single seed descent method. Conventional pedigree secombined pedigree intraselection was proved reliable and effective lection based on visual evaluations may be difficult, in restoring or even improving the local cultivar of snap bean according especially for traits with low to moderate heritability to update demands.such as seed yield (Patino and Singh, 1989). Bulk breeding methods were effective for endowing genotypes with a better yield stability (Allard,...
