Waxy maize with its pure amylopectin starch is the staple food of many ethnic minorities in hilly regions of Southeast Asia （SEA）. A combination of waxy and quality protein maize （QPM） traits would improve the qua...Waxy maize with its pure amylopectin starch is the staple food of many ethnic minorities in hilly regions of Southeast Asia （SEA）. A combination of waxy and quality protein maize （QPM） traits would improve the quality of protein of waxy maize for human consumption. Double recessive waxy-QPM （wx-o2） genotypes had been generated from Southern Chinese material by haploid induction of crosses heterozygous for the two quality traits with an absolutely conserved waxy type and an improved amino acid profile. The vitreous kernel trait （due to the additional modifier genes present in QPM） was lost in the wx-o2 plant material; this may be due to the waxy mutation, this is anyhow desirable for acceptance as waxy maize is preferred due to its soft grains. The content of the quality limiting amino acid lysine was greatly increased in double recessive wx-o2 genotypes compared to standard waxy maize, but still with a high variation among genotypes for future improvement. Conclusively, it was indeed possible to combine two grain quality mutations successfully within one genotype and prototypes of double quality wx-o2 are available now to contribute to meet human requirements in essential amino acids and thus reduce malnutrition in various regions of Asia.展开更多
High temperature(HT)during grain filling is one of the most important environmental factors limiting maize yield and grain quality.Nitrogen(N)fertilizer is essential for maintaining normal plant growth and defense aga...High temperature(HT)during grain filling is one of the most important environmental factors limiting maize yield and grain quality.Nitrogen(N)fertilizer is essential for maintaining normal plant growth and defense against environmental stresses.The effects of three N rates and two temperature regimes on the grain yield and quality of fresh waxy maize were studied using the hybrids Suyunuo 5(SYN5)and Yunuo 7(YN7)as materials.N application rates were 1.5,4.5,and 7.5 g plant-1,representing low,moderate,and high N levels(LN,MN,and HN,respectively).Mean day/night temperatures during the grain filling of spring-and summer-sown plants were 27.6/21.0°C and 28.6/20.0°C for ambient temperature(AT)and 35/21.0°C and 35/20.0°C for HT,respectively.On average,HT reduced kernel number,weight,yield,and moisture content by 29.8%,17.9%,38.7%,and 3.3%,respectively.Kernel number,weight,yield,moisture,and starch contents were highest under MN among the three N rates under both temperature regimes.HT reduced grain starch content at all N levels.HT increased grain protein content,which gradually increased with N rate.Mean starch granule size under MN was larger(10.9μm)than that under LN and HN(both 10.4μm)at AT.However,the mean size of starch granules was higher under LN(11.7μm)and lower under MN(11.2μm)at HT.Iodine binding capacity(IBC)was lowest under MN and highest under HN among the three N levels under both temperature regimes.In general,IBC at all N rates was increased by HT.Peak viscosity(PV)was gradually reduced with increasing N rate at AT.In comparison with LN,PV was increased by MN and decreased by HN at HT.Retrogradation percentage gradually increased with N rate at AT,but was lowest under MN among the three N rates at HT.LN+AT and MN+HT produced grain with high pasting viscosity and low retrogradation tendency.MN application could alleviate the negative effects of HT on the grain yield and quality of fresh waxy maize.展开更多
文摘Waxy maize with its pure amylopectin starch is the staple food of many ethnic minorities in hilly regions of Southeast Asia （SEA）. A combination of waxy and quality protein maize （QPM） traits would improve the quality of protein of waxy maize for human consumption. Double recessive waxy-QPM （wx-o2） genotypes had been generated from Southern Chinese material by haploid induction of crosses heterozygous for the two quality traits with an absolutely conserved waxy type and an improved amino acid profile. The vitreous kernel trait （due to the additional modifier genes present in QPM） was lost in the wx-o2 plant material; this may be due to the waxy mutation, this is anyhow desirable for acceptance as waxy maize is preferred due to its soft grains. The content of the quality limiting amino acid lysine was greatly increased in double recessive wx-o2 genotypes compared to standard waxy maize, but still with a high variation among genotypes for future improvement. Conclusively, it was indeed possible to combine two grain quality mutations successfully within one genotype and prototypes of double quality wx-o2 are available now to contribute to meet human requirements in essential amino acids and thus reduce malnutrition in various regions of Asia.
基金supported by the National Key Research and Development Program of China(2016YFD0300109,2018YFD0200703)the National Natural Science Foundation of China(31771709)+2 种基金Jiangsu Agriculture Science and Technology Innovation Fund(CX[19]3056)the Priority Academic Program Development of Jiangsu Higher Education InstitutionsHigh-end Talent Support Program of Yangzhou University。
文摘High temperature(HT)during grain filling is one of the most important environmental factors limiting maize yield and grain quality.Nitrogen(N)fertilizer is essential for maintaining normal plant growth and defense against environmental stresses.The effects of three N rates and two temperature regimes on the grain yield and quality of fresh waxy maize were studied using the hybrids Suyunuo 5(SYN5)and Yunuo 7(YN7)as materials.N application rates were 1.5,4.5,and 7.5 g plant-1,representing low,moderate,and high N levels(LN,MN,and HN,respectively).Mean day/night temperatures during the grain filling of spring-and summer-sown plants were 27.6/21.0°C and 28.6/20.0°C for ambient temperature(AT)and 35/21.0°C and 35/20.0°C for HT,respectively.On average,HT reduced kernel number,weight,yield,and moisture content by 29.8%,17.9%,38.7%,and 3.3%,respectively.Kernel number,weight,yield,moisture,and starch contents were highest under MN among the three N rates under both temperature regimes.HT reduced grain starch content at all N levels.HT increased grain protein content,which gradually increased with N rate.Mean starch granule size under MN was larger(10.9μm)than that under LN and HN(both 10.4μm)at AT.However,the mean size of starch granules was higher under LN(11.7μm)and lower under MN(11.2μm)at HT.Iodine binding capacity(IBC)was lowest under MN and highest under HN among the three N levels under both temperature regimes.In general,IBC at all N rates was increased by HT.Peak viscosity(PV)was gradually reduced with increasing N rate at AT.In comparison with LN,PV was increased by MN and decreased by HN at HT.Retrogradation percentage gradually increased with N rate at AT,but was lowest under MN among the three N rates at HT.LN+AT and MN+HT produced grain with high pasting viscosity and low retrogradation tendency.MN application could alleviate the negative effects of HT on the grain yield and quality of fresh waxy maize.
