Effects of PP333 on dry matter accumulation and seed yield of Lolium multiflorum

A field experiment was conducted to study the effect of spraying PP333 before jointing on plant height, dry matter accumulation and seed yield of annual ryegrass (Lolium multiflorum var.ganxuan No.2). The results showed that PP333 could inhibit the plant height significantly. With the increasing of PP333 concentration, plant height decreased. PP333 promoted dry matter accumulation and transfer within certain concentration. The dry matter accumulation of treatments in heading stage and mature stage, and the transportation amount before heading were both significant higher than CK. But spraying too much PP333 could decrease the accumulation and transfer of dry matter significantly. Yield components responded differently to PP333, grain weight was less influenced, while grain number per spike and spike number were significantly influenced. Path analysis showed that PP333 had the most effect on spike number which was the key factor in output. The annual ryegrass lodged and shattered severely in mature stage, PP333 could decrease shattering rate and inhibit these phenomena effectively, and the inhibition increased with the increasing of PP333 concentration.