| Eight different genotypic wheat varieties and a RIL population derived from the hybrid of XY54×J411 were used as research materials in this study.Under the same cultivation conditions in the main wheat producing area of Huang-Huai-Hai Plain,the effects of sowing date on the growth and developmental period,yield and quality related traits of different wheat varieties were studied,and QTL analysis for important agronomic traits of wheat under different sowing dates was carried out.The main research results are as follows:1.With the delay of sowing date,the growth and developmental period of different varieties is obviously shortened,and the change of jointing stage is the most obvious one,but there are some differences among different winter and spring wheat varieties.2.With the delay of sowing date,the wheat spike number decreased,and basically,the fertile spikelets of semi-winter varieties increased firstly and then decreased.In 2018-2019 wheat grown season with more extreme weather events,the wheat yield decreased,while in 2019-2020 wheat grown season with less extreme weather events,it increased firstly and then decreased.3.In terms of quality traits,the grain hardness of wheat varieties with the same winter and spring characteristics has the same trend,but there are differences between the years.In 2018-2019,semi-winter varieties increased firstly and then decreased,while winter varieties decreased firstly and then increased.In 2019-2020,the grain hardness of both semi-winter varieties and winter varieties basically increased firstly and then decreased;Relatively,sowing date has little effect on protein accumulation of most varieties,but has obvious genotypic effects on grain wet gluten content.The wet gluten content of JM22 and YN0428 had little change with the delay of sowing date,while that of AK58 and XY54 decreased significantly with the delay of sowing date.4.The influence of sowing date on agronomic traits of the "XY54×J411" RIL population basically is the same as that of other varieties.The delay of sowing date obviously shortened the growth and developmental period of different lines,and the difference between early sowing and late sowing can be up to 35 days.The major differences between the two parents at different sowing dates were the number of sterile spikelets and fertile spikelets,while the response patterns of ear length,plant height,growth and developmental period,and thousand-grain weight to sowing date exist differences between years.5.A total of 136 QTL loci controlling 12 agronomic traits were detected in the two-year field sowing date experiment,which distributed on 21 chromosomes.Among them,67 QTLs were detected in 2018-2019 wheat grown season,and the explained phenotypic variations ranged from 4.2%to 28.12%,and 69 QTLs were detected in 2019-2020 wheat season,and the the explained phenotypic variations ranged from 6.14%to 29.06%.There were 76 QTL loci jointly detected in both years,which located on 19 marker intervals.Most co-localized QTLs regulate different agronomic traits under different sowing dates,and it is suggested that these loci may have pleiotropic or linkage effects.A total of 38 QTL loci expressed in 3 different sowing dates were detected in the two-year experiment in 7 marker intervals,while 23,19 and 13 loci were specifically detected under the conditions of early sowing,middle sowing and late sowing respectively.These results indicate that some of the QTL loci that regulate wheat agronomic traits are stably expressed under different sowing dates,and some are specifically expressed under specific sowing dates.Our results provide a theoretical basis for further optimizing the sowing date of different wheat varieties,and also lay a foundation for analyzing the molecular regulation of the sowing date on the formation of important agronomic traits of wheat. |
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