THE FIELD PEA CROP IN SW AUSTRALIA .2. EFFECTS OF CONTRASTING MORPHOLOGY AND ENVIRONMENT ON REPRODUCTIVE-PERFORMANCE

Reproductive performance of six field pea genotypes was assessed at three contrasting field sites in Western Australia and under optimal conditions in a glasshouse using comparative data on phenology, branching pattern, green area indices, number distribution and fruiting success of reproductive nodes and final seed yields per plant or unit crop area. Two genotypes (Dundale and Wirrega) were tall, indeterminate and conventionally leaved, the other four semi-dwarf and more erect. Three of the latter were semi-leafless (Dinkum, L82 and L80) and the other tare-leaved (Progreta). Seed yields at the field sites increased generally in relation to rainfall during the growing season (May-October), viz. Avondale (267 mm), Wongan Hills (350 mm), Mt Barker (421 mm). Superior performance at Mt Barker was related to greater biomass and green area index and higher number of reproductive nodes and pods per plant, but not to increased branches per plant, pods per node, seeds per pod or seed size. Improved harvest index, larger seeds and greater reproductive yield from basal and aerial branches were responsible for the trellised well-watered and fertilized glasshouse plants mostly outyielding those at the field sites. Field-site specific superiority of certain genotypes over others was evident, e.g. the top ranking performance of the deeper-rooted, late maturing Wirrega at the drier sites of Avondale or Wongan Hills and the much improved performance of the semi-leafless types in the extended cool and moist season of Mt Barker. Poor seed yields of tall types relative to their vegetative biomass were pronounced at Mt Barker due to poor fruit set and seed filling in the severely lodged and self-shaded canopies. Data are discussed in relation to previous cultivar evaluations and ideotype prescriptions by other workers in Australia or overseas.