APHID RESISTANT LUCERNE CULTIVARS IN MID CANTERBURY

Abstract

Six lucerne cultivars (Wairau, Rere, WL318, AS13R, Pioneer 521 and Saranac) were evaluated in Mid Canterbury since 1979 under two contrasting management systems; dryland grazing and irrigated 'cut and cart'. In addition, the effect of strategic aphicide application was examined on the irrigated system. Principal interest in both these studies centred on Rere, the N.Z. bred aphid resistant cultivar released in 1979. All the cultivars established well and for the first three years no consistent differences between cultivars in herbage yield were recorded under either system. However, in the third full production season (1982183) substantial differences in herbage yield began to develop between the cultivars, and the tvzd cnn!inued i:: the fGiiit:l arid fiiiai production season (1983/84). By the end of the fourth season Rere was clearly the lowest yielding cultivar under both systems, producing only 69% and 29% of the yield of the highest producing cultivar (Wairau) under dryland and irrigated conditions respectively. Application of aphicide gave no herbage yield benefit on any cultivar in any season. Keywords: Medicago sativa, irrigated, non irrigated, cultivars, aphicide, Wairau, Rere, WL318, AS 13R, Pioneer 521, Saranac