Partial Substitution of Hybrid Seeds with Open Pollinated Variety in Single Plant and Double Plants per Hill on Grain Yield and Yield Components of Maize (Zea mays L.)

摘要

A field experiments was conducted at the Central Experiment Station of the University of the Philippines at Los Banos to evaluate mixed variety cultivation as productivity-enhancing and cost-saving strategies for maize production. The experiment was laid out in randomized complete block design with factorial arrangement of treatments in three replications. The variety DK 909, a hybrid was substituted with USM var 5, an open pollinated variety (OPV) of maize. Mixed variety cultivation involved mixed stands of hybrid and open pollinated variety planted in single plant and double plants per hill. Two maize varieties currently grown in commercial scale in the Philippines were used in the study. Seed substitution significantly influenced grain yield. Nevertheless, there was no effect of interaction between seed substitution x number of plants per hill. Likewise, the differences in 100-grain weight, grain weight per plant, ear diameter, ear length, percentage of ear fill, and shelling recovery were not significant. Grain yield from the mixed stands of 75:25 and 50:50 in between hybrid and OPV were comparable with that of the pure stand of the hybrid. Substituting 75% of the recommended seed rate of the hybrid with OPV, however, resulted in significantly lower grain yield by 1,565 kg/ha. However, plant and ear heights were significantly affected by the interaction between seed substitution level x number of plants/hill. Simple regression analysis showed that grain weight per plant and percentage of ear fill accounted for 39% and 30% of the variations in grain yield, respectively. Therefore the study suggested that hybrid seed substitution could be done by OPV up to 50% levels in the subsistence agriculture. Economic analysis for cost and benefit showed that gross return was slightly higher in the pure stand of hybrid than that of 75:25 mixed stands of hybrid and OPV. The pure stand of the OPV gave the lowest gross return, cost of seeds, and return above variable cost.