EFFECT OF IRRIGATION AND FERTILITY LEVELS ON SEED YIELD AND YIELD ATTRIBUTES OF BRASSICA SPECIES

An experiment was conducted during the winter season of 1991-92 and 19 92-93 to study the effect of irrigation and fertilizer on seed yield a nd its characters of Brassica species. Irrigation and fertility levels increased the yield attributes to contribute toward the seed yield. G enotype 'C 6 YS7B' of ethiopian mustard (Brassica carinata A. Braun) g ave maximum seed yield (1.75 tonnes/ha), followed by indian mustard [B rassica juncea (L.) Czernj. & Cosson] (1.63 tonnes/ha) and gobhi sarso n (Brassica napus L. ssp oleifera DC. var annun L.) (1.47 tonnes/ha). One irrigation at 50% flowering stage and irrigation water (IW) : cumu lative pan evaporation (CPE) ratio 0.25 gave optimum yields under limi ted water availability. ie 1.64 tonnes/ha and 1.63 tonnes/ha respectiv ely. Two irrigations (at 50% flowering + 25% siliqua-formation. stage) and 1W : CPE 0.40 also increased the seed yield giving 1.69 tonnes/ha and 1.74 tonnes/ha respectively. However, the crop without irrigation gave 1.36 tonnes/ha only. Mean seed yield under fertility levels N60P 9.7 (60 kg N/ha + 9.7 kg P/ha), N80P12.9 and N100P16.0 was 1.51, 1.65 and 1.68 tonnes/ha respectively. The stover yield also showed a simila r trend.