BEAN SEED QUALITY: ASSOCIATED GERMINABILITY AND FIELD PERFORMANCE

Abstract

This work aimed to investigate the influence of differentlevels of bean seed quality on germinability (laboratory study),growth, yield and its components (green pod and dry seed yield)under field conditions. To achieve this study, the seed lot of bean(cv. Giza 3) was manually separated into three classes; light(33.79-38.02g 100-1 seeds; in 2005 season) and (34.39-37.13g 100-1seeds; in 2006 season); ungraded (37.70-42.85g 100-1 seeds; in2005 season) and (40.02-49.81g 100-1seeds; in 2006 season) andheavy (47.20-57.60g 100-1 seeds; in 2005 season) and (48.75-57.13g 100-1 seeds; in 2006 season). Under field conditions, seedsof bean were sown during two summer successive seasons of 2005and 2006 at the experimental station, Faculty of Agriculture,Fayoum University, Egypt. The obtained data could besummarized as follows:High-weight class of bean seeds usually exhibited faster andmore uniform rates of radicle emergence (as indicator ofgermination) than low-weight and ungraded ones. Seedlingproduced from heavier seeds had greater rates of QI, VI, length ofradical hypocotyl and accumulation of fresh and dry weights thanthose from light seeds. The water uptake%, EC and the quantity ofmaterials leached from the seed (Na, K, Pi, sugars, free aminoacids and Ao260 and Ao280 absorbing materials) during imbibitionwere inversely related to seed weight. It is suggesting thatinterferences existed during seed development or deterioration hadoccurred in the low weight seed.It can be noticed that seed quality of bean significantlyaffected field performance of bean plants and resulted in anincrease of the studied plant growth traits (plant height, No. ofleaves, No. of branches, leaf area leaf-1, leaf area plant-1, fresh anddry weights of leaves plant-1, fresh and dry weights of branchesplant-1, and total fresh and dry weights of shoot plant-1) withincreasing the level of seed quality class. It can be seen that therewas a close relation between seed quality of bean and green podsyield and its components. In this respect, No. of green pods plant-1,weight of green pod, green pod yield plant-1 and feddan-1 wereincreased as seed quality class was increased. It was found thatbean dry seed yield and its components; empty and seeded podsplant-1, total No. of pods plant-1, grades of dry seeded pods, No. ofseeds plant-1, seed yield plant-1 and feddan-1 and seed index (100-seed weight) was positively correlated with the class of sownseeds, the seeds which gave plants with high yield of dry seedsand its components were high in their quality and vice versa. Itwas shown that seed quality class markedly affected chemicalconstituents concentration of the different organs of bean plants produced from the different seed classes. In this respect, the highseed quality class significantly increased total sugars (total solublecarbohydrates in dry seeds), protein, N, P, K, Fe, Mn and Zn inleaves, green pods and dry seeds over that of light and ungradedseed classes.Finally, in the light of the preceding results, it may beconcluded that the results obtained suggest that the weight-seedseparation of bean may enable for significantly improvedgermination and seedling growth. Also, high quality bean seeds toexhibit higher percent field performance and resulted in uniformityand establishment which reflected in high green pods and dry seedyield of bean either plant or feddan-1. Thus, it concluded that it islikely that farmers by sowing seeds of high seed quality, willobtain yield increases of bean (green pods and dry seed).