Study On Proliferation Discipline Of Endosperm Cell In Maize Hybrid And Its Parents

Maize yield has significant heterosis,and the grain weight of hybrids is also significantly higher than that of the parents.The number of endosperm cells in one kernel,the cell size of endosperm cell,the number of starch granule,and starch granule diameter all have impact on the grain weight.In order to study the proliferation of endosperm cells of inbred lines and its effect on the grains of hybrids,this study was conducted in 2019-2020.The hybrids Xianyu335,Zhengdan958 and their parents were mainly promoted as experimental Material to study the rule of grain weight,endosperm cell number and starch granule number between hybrids and the parents,and provide a basis for breeding in maize.The results are as follows:1.The ear characters of the two hybrids have heterosis.Hybrids Xianyu335 and Zhengdan958 have obvious over high parent heterosis in ear characters such as ear diameter,cob diameter,ear length,cob weight,kernel row number and kernel number.Grains number per ear and 1000-grain weight of the two hybrids have higher heterosis.The over high parent heterosis(161.11%)of grain weight per ear in Zhengdan958 is higher than that of Xianyu335(91.77%),and the over high parent heterosis(74.29%)of grains number per ear in Zhengdan958(74.29%)is higher than that of Xianyu335(44.19%),and Xianyu335’s 1000-grain weight with over high parent heterosis(27.53%)is higher than that of Zhengdan958’s(18%).2.Number and size of endosperm cells.The proliferation of the endosperm cells of the two Material and their parents showed an"S"-shaped curve change:3-5 days after pollination is a slow growth period,10-20 days after pollination is a rapid growth period,and the number of endosperm cells in the 6 materials reaches the maximum at 20 days after pollination.The maximum number of endosperm cells per kernel in descending order is:Zhengdan958>Zheng58>Chang7-2,Xianyu335>PH4CV>PH6WC.Zhengdan958 has 1.112million endosperm cells in one kernel,significantly higher than that of Xianyu335.The over high parent heterosis of endosperm cell number per kernel in Xianyu335(861.6×10~4)is22.34%,that is 29.24%in Zhengdan958.The endosperm cell volume of hybrid Xianyu335 is smaller than that of its parents,while the cell size of hybrid Zhengdan958 is between the two parents,and the cell volume of Xianyu335 is larger than that of Zhengdan958.3.Number and diameter of starch granules.Different Material starch granules have different particle size:Zhengdan958’s starch granule diameter is lower than that of its parents,while Xianyu335’s starch granule diameter is between its parents.The over high parent heterosis(5.38%)of starch granule number in Xianyu335 is higher than Zhengdan958.4.The contribution of endosperm cells and starch grains to seed weight in two hybrids.Xianyu335 has a slightly smaller endosperm cell volume than its parent PH4CV,but the starch granule diameter,number of starch granule,and endosperm cell number are significantly higher than that of its parents.Therefore,Xianyu335 has a higher grain weight,large kernel volume.Compared with its parents,Zhengdan958 has smaller starch granules in per endosperm cell and fewer number of starch granules than its parents,but the endosperm cell size and cell number are more than its parents.Therefore,Zhengdan958 has larger grain and higher grain weight.That is to say,the mechanism of the grain size is different between the two Material,which has important guiding significance for maize breeding.