Abstract
The endosperm chalkiness in grains is one of the most important traits in rice grain qualities, and grain chalkiness directly determines grain quality and market price. Therefore, the endosperm chalkiness reduction is an important goal of breeding scientist in rice. However, little is known about the relationship of the formation of rice endosperm chalkiness and the morphological structure and development in fragrant japonica and conventional japonica varieties. In this study, we have mainly investigated the chalkiness characters such as degree of endosperm chalkiness (DEC), chalkiness rate (CR) and chalkiness area (CA) in 12 fragrant japonica varieties and 9 conventional japonica varieties. Furthermore, the endosperm structure and starch granules of rice grains were also observed with scanning electron microscope (SEM). The results indicated that the 21 varieties including the different fragrant japonica and conventional japonica varieties has a linear relationship between the DEC and the CR (P < 0.05). Among the fragrant japonica and conventional japonica varieties, the biggest difference is the CR, follow by CA and DEC. In addition, there is a certain correlation between the arrangement of endosperm cells, the distribution of starch granules and the occurrence of chalkiness characters in the different fragrant japonica and conventional japonica varieties. For the same fragrant japonica or conventional japonica variety, there is no significant difference between the starch granules from the transparent parts of chalkiness and non-chalky, while the starch granules of grains between chalky and non-chalky has obvious difference. Our results would provide important references for high quality rice breeding.
Highlights
Rice (Oryza sativa L.) is one of the most important food crops in the world, and the staple food for more than half of the world’s population (Balindong et al, 2018; Zhao et al, 2013)
Change trend of degree of endosperm chalkiness (DEC) was quite similar to the chalkiness rate (CR) in the 21 japonica varieties, and the DEC ranged between 0.3% and 100%
The results indicated the close correlation between the shape and arrangement of starch granules with occurrence of grain chalkiness characters in fragrant japonica and conventional japonica varieties
Summary
Rice (Oryza sativa L.) is one of the most important food crops in the world, and the staple food for more than half of the world’s population (Balindong et al, 2018; Zhao et al, 2013). Vol 10, No 7; 2018 appearance, eating, nutritional, cooking and eating qualities (Tian et al, 2009; Peng et al, 2014; Liu et al, 2010) Among these qualities, consumers often focus on appearance quality and cooking and eating quality (Guo et al, 2011; Cuevas et al, 2016). Chalkiness characters will reduce head milled rate and affect its production in grain, and has a great impact on the price of rice (Cuevas et al, 2016; Sun et al, 2015; Zhao et al, 2013). Grain chalkiness character is the main determinant of grain qualities and market value of rice
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