EFFECT OF TIME OF SOWING ON FLOWERING IN FABA BEAN (VICIA-FABA)

Sequential sowings of faba bean (Vicia faba) were conducted to examine the effect of sowing date and a vernalisation treatment on the phenol ogy of a range of faba bean accessions. There was very little differen ce between accessions in the rate of germination. Delayed sowing incre ased the time to establishment, but the thermal time from sowing to em ergence did not vary greatly. On average 208-degrees-C.day was require d for emergence and the base temperature for germination was near 0-de grees-C for all accessions. The shortest time from emergence to first flower averaged over all sowing dates was 43 days for Accession 286 (r ange 29-52 days), and the longest was 73 days for Accession 863 (50-96 days). The greatest response to vernalisation occurred when the seed was sown in early autumn (April). When sown in late winter (August), h owever, there was little response to vernalisation despite the plants being exposed to higher mean temperatures. In that case, long and leng thening days partly overcame the vernalisation requirement of some cul tivars. For the range of sowing dates normally expected in dryland cro ps in southern Australia, there was little effect of vernalisation on the time to flowering and the major controls of development were throu gh responses to temperature and daylength. The range of maturity types in the current breeding program appears sufficient to extend the rang e of environments in which faba bean is grown.