A Study On Effects Of Two-cultivar Mixture Of Winter Wheat (Triticum Aestivum L.) Under Different Sowing Densities

Cultivar (or variety) mixture has been paid attention on by many for its advantages over pure stands on yield, yield stability, disease resistance, grain quality, etc. There have been lots of researches on this topic in the world, among which many have been done with Triticeae crops. This study uses two winter wheat cultivars with different plant height, Jing-9428 and Shiluan 02-1, to study the effects of two-cultivar mixture under various sowing densities. The two varieties were sown in pure stands and inter-sown with 1:1 row ratio in mixture under 5 sowing densities respectively. Plant parameters at each growing stage, yield components, yield etc., were measured. The main results were as follows:Plant height, shoots per plant, number of secondary root per plant at heading, productive tiller percentage, etc., are all higher in mixtures than in pure stands for the higher cultivar Jing-9428, but lower in mixtures than in pure stands for the shorter cultivar Shiluan 02-1. There is no significant difference in plant height between the same cultivar in mixtures under different sowing densities.Shoot number on unit area and LAI in mixtures are higher than it in pure stands of Jing-9428 and lower than it in pure stands of Shiluan 02-1.The mixture has an effect on grain filling at late growing stage. Grain filling of Jing-9428 in mixture is faster than that in pure stands, while grain filling of Shiluan 02-1 in mixture is slower than that in pure stands. The mixtures have a biomass a little higher than pure stands under higher sowing densities.Under lower sowing densities, harvest index of the mixtures is higher than it in pure stands for Jing-9428 and lower than it pure stands for Shiluan 02-1. Under higher densities, harvest index of the mixtures is lower than both of the two varieties in pure stands.The mixture also affects ear density on unit area, kernel number per year and kernel weight. All the yield components of Jing-9428 are higher in mixtures than those in pure stands, while the components of Shiluan 02-1 are all lower in mixtures.Yields of Jing-9428 are higher in mixtures than in pure stands, while yields of Shiluan 02-1 are lower in mixtures than in pure stands under all sowing densities. The yield of mixture is higher than in pure stands only under the density of 600.0×10~4 seedlings/hm~2, and in other densities, all of the gross yields are higher than Shiluan02-1 and lower than Jing-9428 in pure stands respectively. Relative yield total (RYT) of the mixtures under all sowing densities are higher than 1, indicating that there is a advantage of higher yield of the mixture over pure stands.The mixtures can improve the ability of resist lodging significantly compared to the pure stand which plant height is higher comparatively.