Differences And Effects Of Cultivation Techniques On Starch Viscosity In Waxy Corn

The differences of starch viscosity among varieties and the correlations of RVA viscosity characteristic related with grain yield and quality were investigated, the effects of main cultivation techniques on the starch viscosity characters were analyzed. The experiment was carried out in the experimental farm of Yangzhou University in 2004-2005.The main results were as follows:1. Differences of starch RVA viscosity among varieties in waxy maizeSeven starch viscosity characters differed significantly among varieties. Significant positive correlation(P0.01) were observed among peak viscosity(PV), trough viscosity(TV), final viscosity(FV), breakdown(BD) and setback(SB), PV was significantly negative correlated with peak time (PT) and pasting temperature(PTP), BD was significantly negative correlated with PT and PTP, PT was significantly positive correlated with PTP.2. Relationship of starch viscosity to grain qualitySome characters of fresh food quality, ratio of pericarp and residue,ratio of amylopectin to total starch differed significantly among varieties. PV,FV and BD were significantly positive correlated with mucosity and tender, TV was significantly positive correlated with mucosity, SB was significantly negative correlated with savour and pericarp thickness. Ratio of amylopectin to total starch was significantly positive correlated with PV,TV, FV and BD, and was significantly negative correlated with PT and PTP. Ratio of pericarp and residue was significantly positive correlated with PTP.Total strach contents was significantly positive correlated with BD and PV, PV,BD were significantly negative correlated with protein content, and SB was significantly negative correlated with grain reductive sugar content. PT was significantly correlated with protein and total strach content. PTP was significantly negative correlated with protein and total strach content.3. Relationship of starch viscosity to grain yieldFresh ear yield ,fresh kernel yield and maturity kernel yield differed significantly among varieties. The correlation of starch viscosity characters to fresh ear yield ,fresh kernel yield and maturity kernel yield were not significant. By using fresh ear yield ,fresh kernel yield, maturity kernel yield and PV,TV,FV as indexes, cluster analysis of 32 varieties were done, Tiannuo5 was regarded as high yield and high PV,TV,FV, ten varieties had high fresh ear yield and high PV,TV,FV, five varieties had high fresh kernel yield and high PV,TV,FV.4. Effects of cultivation techniques on the starch viscosity characters of waxy maizeStarch viscosity characters were significantly different under different densities, PV, TV, FV, BD and SB under 8.25×104 plants/ha were higher than under 5.25×104 plants/ha, while the PT and PTP were on the contrary. PV, BD were significantly negative correlated with protein content, PT, PTP were significantly negative correlated with reductive sugar content. The correlation of starch viscosity characters to Fresh ear yield ,fresh kernel yield were better than to maturity kernel yield. Starch viscosity characters were significantly different under different application amount of nitrogen fertilizer at Jointing stage, PV, TV, FV, BD and SD were presented a tendency of 300kgN/ha>0kgN/ha>150kgN/ha with increasing of N level, while PT and PTP were presented a tendency of 150kgN/ha>0kgN/ha>300kgN/ha. There were no clear correlations between viscosity characters and grain quality, only PTP were significantly correlated with maturity kernel yield.Starch viscosity characters were significantly different under different sowing date, PV, TV, FV, BD, PTP were presented higher in spring-sowing, while SB and PT were presented higher in autumn-sowing. Total starch content was significantly negative correlated with TV, FV, and PTP. PV, BD, PTP were significantly correlated with fresh ear yield, fresh kernel yield and maturity kernel yield.