Effect of Various Growth Parameters on Seed Yield of Iron Weed

Abstract

Iron Weed (Vernonia anthelmintica) has immense potential for cultivation as a commercial crop on marginal lands, particularly in the semiarid agroclimatic conditions of the country. As nothing was known previously regarding its potential as commercial crop, we intended to evaluate its available germplasm for seed yield in the Pakkhal Plateau of District Mansehra. Performance of the germplasm was evaluated through the application of different sowing methods, seed rates, herbicide application, and plant density. The parameters included plant height (41.6–75.7 cm), number of leaves per plant (12–17), number of branches per plant (6–10), leaf area (18.5–45.3 cm2), number of capitula per plant (40–69), and yield per hectare (273–543 kg). Analysis of variance showed highly significant difference for yield component traits. The correlation coefficient indicated that seed yield had highly significant and positive correlation with number of capitula per plant and number of branches per plant, significant and positive correlation with plant height and nonsignificant positive correlation with leaf size and number of leaves per plant. Similarly seed yield had very strong, highly significant, and positive regression with 7.867 and 5.602 regression coefficients for number of capitulum and number of branches, respectively. Weak, positive, and significant regression with 5.221 regression coefficient for plant height and weak, positive but nonsignificant regression with 3.858 and 5.602 regression coefficient for leaf area and number of leaves, respectively. It is concluded that both the planting method and herbicide application have evident effect on seed yield in Iron Weed. For getting maximum yield it is recommended that in the rainfed conditions it should be sown by broadcast method, with herbicide sprayed before sowing. Agronomic characters like number of capitulum per plant, number of branches per plant, and plant height have evident effect on seed yield; hence, these characters must be taken on preference for Vernonia improvement.