Rw. Williams et al., STUDIES ON WATER DAMAGE IN MUNGBEAN .1. EFFECT OF WEATHERING ON SEED QUALITY AND VIABILITY, Australian Journal of Agricultural Research, 46(5), 1995, pp. 887-899
The expansion of mungbean production in Australia is severely limited
by the susceptibility of current cultivars to weather damage in the fi
eld. The aim of this research was to describe the causes, process, and
effects of weathering in mungbean as the first step toward the breedi
ng of resistant cultivars. Symptoms of weather damage were produced by
exposing plants to simulated rainfall/high humidity and by subjecting
seeds to cycles of wetting and drying. In both cases, symptoms progre
ssed from discolouration, wrinkling, and cracking of the testa, to ger
mination of the seed. Symptoms produced in controlled experiments were
the same as those observed in the field. Only seeds that imbibed duri
ng the wetting phase developed symptoms of weather damage on drying. E
xposure to one cycle of weathering also advanced the timing and degree
of damage to seeds during subsequent cycles. This was associated with
an increased rate of water absorption in weathered seeds. The lowerin
g of apparent resistance to weather damage with prior exposure to rain
fall suggested that only protected material be screened for weathering
resistance. The death of seeds remained the ultimate expression of th
e changes induced by weathering.