The influence of mineral nutrition, stage of harvest and flower position on seed yield and quality of phaseolus Vulgaris L.

Abstract

In this work the effects of mother plant nutrition and flower position on the plant in relation to different harvest stages on French beans (Phaseolus vulgaris L. cv. Cascaded; seed yield, quality and progeny performance have been studied. In three pot experiments under glass and one in the field, different levels of nitrogen, phosphorus, potassium and molybdenum were applied to the mother plant and it was found that higher seed yields were obtained with the higher nutrient levels tested, but these high seed yields were not necessarily accompanied by high quality. Seed yield and quality increased with the increase of nitrogen and potassium. The phosphorus effect however, was different, in that the seed yield increased in relation to the levels but the seed quality decreased. Molybdenum was found to be necessary in moderate amounts, especially for the seed quality. The interactions between nitrogen and phosphorus levels (NP) and between nitrogen, phosphorus and potassium (NPK) were found to be very important for bean seed quality, because their significant effect was similar and constantly present in most of the seed vigour components examined. It seems that the combinations of high nitrogen levels with moderate amounts of phosphorus applied to the mother plant resulted in seed of good quality. In one pot experiment under glass the progeny performance was examined, using seed from the 1st mother plant nutrition experiment and it was found that the mother plant nutrition affected the progeny in it*s early stages. This effect disappeared later and no difference in progeny seed yield was found. In two pot experiments under glass the bean pods were harvested at different stages and the pods from the main axis were separated from the pods on the secondary branches grown mainly from the axils of the primary leaves. It was found that the quality of seed from the secondary branches was lower than the quality of seed from the main axis. However, this difference in seed quality became less with the later harvests. The following tests were used to assess seed quality: the official germination test, seedling evaluation test, cold test, and electrical conductivity test. In addition, the seed size was determined and the seeds were analysed for total nitrogen, phosphorus and potassium content.