GROWTH INTERACTIONS OF NAVY BEAN VARIETIES WITH SOWING DATE AND SEASON

Five navy bean (Phaseolus vulgaris L.) varieties were sown monthly fro m December to February at Kingaroy in 1991-94, plus a November plantin g in 1993 and 1994, to investigate how varietial differences may be af fected by time of sowing. For grain yield there were seasonal interact ions with both sowing date and variety, with maximums for a December s owing in 1991 and 1994 but a minimum in 1993 for November and December sowings due to infection with grey mould (Macrophomina spp.). Yields were least with the February sowing in 2 years and for mean yield over years. The early maturing varieties, Actolac and Pan 12, maximised yi eld with a January sowing, and the late varieties, Sirius, Rainbird an d Spearfelt, with a December sowing. Time to flowering and maturity wa s greatest for November plantings, while minimum time to flowering and maturity was subject to marked interactions with varieties and season . Determinate varieties Rainbird, Spearfelt and Actolac were non-viny across sowing dates, while semideterminate Sirius and Pan 12 were less viny with later sowing. Canopy height, pod height and lodging were af fected by interactions amongst varieties, seasons and sowing dates, wi th lodging tending to increase with canopy height and yield gains. Pod height was correlated with canopy height and was greatest for varieti es Sirius and Rainbird. Spearfelt consistently had low lodging. Decemb er-January sowing is recommended for Sirius, Rainbird and Spearfelt, a nd a January sowing is recommended for Actolac and Pan 12.