Growth responses of soybean [Glycine max (L.) Merr.] to drought and aluminium stress.

Abstract

The government has launched the soybean self sufficiency by 2014 in an effort to enough needs domestic of soybean . This will be achieved by increased productivity , expansion of cropping intensity and extension of planting area. A extension of the planting area is to utilize marginal lands. The mostly marginal lands in Indonesia is dryland acid soil and has the potential to be developed as an extension of planting area. The cultivation in dryland acid soil had several constraints, such as drought and high solubility of Al3+. The soybean response to water deficit varies depending on the genotypes, and the duration of the stress and growth phase. High solubility of Al3+ in the soil inhibits root growth. The experiment was carried out to study the growth response and the mechanisms of adaptation the soybean genotypes to drought and aluminum stress, which consists of the two stages experiments. The first stage was carried out to study the effect of genotype, drought and aluminium stress on the vegetative and generative growth and the plant roots of soybean. The second stage was carried out to study the effect of genotype, drought and aluminium stress on component crops of soybean. This experiments was conducted in Januari to November 2011, in the greenhouse Cikabayan, University Farm, IPB Darmaga Bogor. This study used a randomized complete block design, with three factors: 1) soybean genotypes (SP 30-4, Anjasmoro, PG 57-1 and Tanggamus), 2) watering interval (2 days, 6 days and 10 days, 3) the level of Al neutralization (0% neutralization and 100% neutralization). The results show that the adaptation mechanism avoidance of soybean geno types was only seen in PG57-1 on root length variables when gripped by drought. This mechanism can be seen from its root elongation when gripped by drought. The higher of value of the observed variables would be the higher the number of pods produced. It also happens to variable root dry weight and dry weight of root nodules. In general, yield components of soybean more influenced by drought stress. However, flowering only variable affected by Al stress on different genotypes.