Abstract:

The effects of different irrigation schemes in both the amount of water applied (45 mm water every time with maximum total 45-315 mm water) and the timing of water applications (7-28 days) after anthesis on the quality characteristics of the strong gluten wheat (Triticum aestivum) `Yumai 34' and the soft gluten wheat `Luoyang 8716' were studied in Zhengzhou and Luoyang experimental sites in Henan Province during the 1999-2001 growing seasons. All natural precipitation was excluded from the controlled experiment. The experiment included eight irrigation treatments: irrigating on the 7th day, the 14th day, the 21st day, the 28th day, the 7th day plus the 14th day, the 7th day plus the 21st day after anthesis and a treatment of irrigating on the 7th, 14th, 21th and 28th days after anthesis and one treatment with no irrigation after anthesis. We summarize the main results below. 1) The content of wet gluten and sed.value increased by 12%-17% under the treatment of no irrigation and 21%-35% under a single, late water application following anthesis. In irrigation treatments that consisted of two or more applications after anthesis, increases were very small. The general tendency was that the greater the amount of water applied, the smaller the value of wet gluten and sed. value. 2) In irrigation treatments that consisted of only one application following anthesis, quality indicators such as dough development time, stability time, and valorimeter value, all increased (the increase ranged from 12%-76% in different cultivars and treatments) when irrigation was late (21-28 days after anthesis). These quality indicators all decreased when there was too much irrigation water (>90 mm) or when applied more than one time. Soften degree became large when irrigation was high (>90 mm). 3) Comparing values between the two cultivars, those of `Yumai 34' were larger than those of `Luoyang 8716', including quality and yield. The variation coefficients of the strong gluten wheat `Yumai 34' were larger than those of weak gluten wheat `Luoyang 8716' which showed that traits of `Yumai 34' changed easily under changing environmental conditions. Changes in the coefficients of water absorption and wet gluten were very small and appeared to be affected mainly by genetics with little environmental effect. The correlated coefficients among sed.value, development time, stability time, and valorimeter value were positive and significant, but correlations between soften degree and other quality items were negative but not significant. 4) Irrigation treatments that consisted of one application only after anthesis tended to produce lower yields, and the later the irrigation time, the lower the yields. In contrast, when the wheat was irrigated more than once, yields tended to increase and, in general, the more water applied, the greater the yields. Generally, under irrigation levels of 180-315 mm without natural precipitation, moderate increases in yield (5 792-8 161 kg•hm-2) were gained. Cultivar `Yumai 34' has a greater yield potential under water conservation strategies whereas `Luoyang 8716' could realize higher yields under sufficient water supply. Considering the quality, yields and the water use efficiency, irrigating on 7th day or 14th day after anthesis was suitable for strong gluten wheat cultivars like Yuami34 to get high yield and quality. For weak gluten wheat cultivars, such as `Luoyang 8716', the best irrigation strategy was at least 2 application times after anthesis to improve yields and quality.