以旱稻品种IRAT109的116个株系与水稻品种越富杂交构建的DH群体及其亲本，在水、旱2种栽培条件下种植，研究了稻米加工、外观、蒸煮和营养等品质性状的变化规律及其各品质性状间的相关性。结果表明，在11个稻米品质性状中，蛋白质含量、整精米率、胶稠度和碱消值等4个性状水、旱2种不同栽培条件下差异较大，说明这些性状受水分条件影响较大；粒长、粒宽、直链淀粉含量和垩白率也有一定的差异，一定程度受土壤水分环境影响。旱栽条件下稻米蛋白质含量、整精米率、胶稠度、碱消值等均有不同程度的升高，其中蛋白质含量平均提高37.9%，平均增加3.02个含量百分点，而垩白率下降，稻米米粒变小，总体上旱栽稻米品质有变优趋势。糙米率、精米率和长宽比在2种栽培条件下没有差异，基本上不受土壤水分环境影响。此外，对同一品质性状在水、旱2种不同栽培条件下相关性分析，表明加工品质性状的基因与环境互作较大，外观、蒸煮和营养等品质性状比较稳定。因此，通过水稻和旱稻相互杂交，可将旱稻的抗旱基因导入外观品质、蒸煮、食用品质以及营养品质优良的目标水稻亲本中，选育出抗旱、优质的水稻或旱稻品种。
Rice is one of the main staple food crops in the world, but rice production almost occupies 70 percent of the total water consumption of agriculture in China. To save water resources, improving rice drought resistance is a major goal in rice breeding, and water-saving rice culture (dry-cultivation) is also with a great potential. Most of the rice quality characteristics are controlled by quantitative genes and also affected by environment. Rice grain quality is different under water- and dry-cultivation environments on which comparative studies are very important for rice breeding and cultivation.
A doubled haploid (DH) population consisting of 116 DH lines developed through anther culture of the F1 hybrid between an upland rice cultivar ‘IRAT109’ and a lowland rice cultivar ‘Yuefu’ was used in this study. The parents and the 116 DH lines were planted in water- and dry-cultivation systems, on the experiment farm of China Agricultural University in 2002. Seeds of parents and 116 DH lines were harvested at maturity, and used to measure the content of crude protein, brown rice percentage, milled rice percentage, head milled rice percentage, amylose content, gel consistency, alkali value, chalkiness, grain length, grain width, and grain length/grain width. All data were analyzed by SPSS software.
The correlation analyses were conducted between quality characteristics in the two cultivated systems. The results indicated that the content of crude protein, head milled rice percentage, gel consistency and alkali value were higher, and chalkiness, grain length and grain width lower in dry-cultivation than in water-cultivation (Table 1). In general, most of characters of rice grain quality were improved in dry-cultivation compared with that in water-cultivation. The content of crude protein, head milled rice percentage, gel consistency and alkali value were more sensitive to water-stress, as compared with amylose content, grain length, grain width and chalkiness. Especially, the content of crude protein was increased by 37.9% or 3.02 percentile in dry-cultivation than in water-cultivation (Fig.1). But brown rice percentage, milled rice percentage and the ratio of grain length/grain width were not influenced by cultural environment. In addition, milling quality characters were affected by the interaction of gene and environment (culture system), but the appearance, cooking and nutrition quality characters mainly controlled by genetic factor. Therefore, the grain quality of the lowland or upland rice cultivars with drought-resistance could be improved under upland condition or dry-cultivation by the cross between lowland rice cultivar with elite grain quality and drought-resistant upland rice cultivar.
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