EFFECT OF WEED COMPETITION PERIODS ON THE GROWTH AND YIELD OF BLACK SEED (Nigella sativa L.)

An investigation to determine the effect of weed competitionperiods on the growth and yield of black seed (kalwanji) was carriedout at the agronomic research area, university of agriculture,faisalabad during 2006-07 growing season. the treatments comprisedof seven weed competition periods (no competition, competition for40, 50, 60, 70 and 80 days after emergence and competitionthroughout the growing season). the experiment was laid out in rcbd(randomized complete block design) with four replications. the netplot size was 1.2 x 5m2. the dominant weeds in the experimentalarea were phalaris minor, chenopodium album and convolvulusarvensis. data on desired parameters were recorded by using standardprocedures. the results showed that the weed control practicesincreased the seed yield per hectare over weedy check by 69.41% byaffecting different growth and yield components like number of plants,number of branches, number of capsules, number of seeds percapsule, 1000-seed weight and total biomass significantly by weedcompetition periods. all the components were decreased progressivelyby increasing weed competition periods in black seed.