Variation Analysis Of Starch Content Of Xinjiang Wheat Landraces And Cultivars In Spring And Winter Wheat Between Two Ecological Points Located In The Northern And Southern Of Xinjiang

The starch of wheat grain plays an important role in determining the yield and quality of wheat.Wheat starch is further divided into amylose and amylopectin.Genetically,wheat starch is synthesized by various enzymes,of which GBSSI,also called Wx proteins,is one of the key enzymes for the synthesis of wheat amylose.Allelic variation of Wx proteins could affect both the content of amylose and the ratio of amylose/amylopectin,thus affecting the quality of wheat.Besides,environment is another factor that affects the content of wheat starch.In this study,we analyzed the Wx gene compositions of 343 Xinjiang wheat that included landraces and cultivars in spring and winter wheat by allele specific molecular makers.Further,90 wheat landraces and cultivars in spring and winter wheat each was planted in two standard ecological points of Xinjiang: Norther Xinjiang and Southern Xinjiang.The starch content,amylose content,amylopectin content and the ratio of amylose/amylopectin were investigated in these wheats.The main results are as follows:1.It was shown that all the Xinjiang wheat germplasms contained Wx-A1 a and Wx-D1 a in Wx-A1 and Wx-D1 and the 155 landraces and 21 cultivars in winter wheat harboured Wx-B1 a by using allele molecular markers of two specific for Wx-A1,six for Wx-B1 and two for Wx-D1.A total of six Wx-B1 alleles were identified in 145 landraces and 22 cultivars in spring wheat,of which 116 landraces and 12 cultivars,two landraces and eight cultivars,two cultivars,and 23 wheat landraces contained Wx-B1 a,Wx-B1 b,Wx-B1 e,and Wx-B1 n,respectively.In addition to these known alleles,two putative novel alleles,namely novel type1 and type 2 were respectively identified in one and three accessions of landraces.2.The starch content of 180 Xinjiang landraces and cultivars in spring and winter wheat that planted in Northern and Southern Xinjiang were investigated,the results shown that wide variation in the content of total starch,amylose,amylopectin and the ratio of amylose/amylopectin were occurred among wheat materials.For spring wheat landraces,the content of total starch,amylose,and amylopectin and the ratio of amylose/amylopectin in Northern Xinjiang were respectively significant higher than those in Southern Xinjiang.For spring wheat cultivars,the content of amylose and amylose/amylopectin in Northern Xinjiang were respectively significant higher than those in Southern Xinjiang,the content of total starch,amylose,and amylopectin,and the the ratio of amylose/amylopectin in Southern Xinjiang were significantly larger than those of in Northern Xinjiang.On the contrary,the content of total starch,amylose,and amylopectin in winter wheat landraces in Southern Xinjiang were significantly larger than those in Northern Xinjiang.But for the Xinjiang winter wheat cultivars,only the amylose in southern Xinjiang significantly larger than that in Northern Xinjiang.There were five Wx-B1 alleles,namely Wx-B1a(69 accessions),b(4),e(2),n(14)and unknown type 1(1)in 90 landraces and cultivars in spring wheat.The ecological points had different effects on the content of total starch,amylose and amylopectin,and ratio of amylose/amylopectin among diffrent alleles.In the case of Wx-B1 a,the total starch and amylose content,and the ratio of amylose/amylopectin in Northern Xinjiang were significantly higher than that in Southern Xinjiang.For Wx-B1 b,the total starch and amylopectin content in Northern Xinjiang were significantly higher than those in Southern Xinjiang,but the amylose content and the ratio of amylose/amylopectin showed opposite results as that in total starch.For Wx-B1 n,the amylose content and the ratio of amylose/amylopectin in Northern Xinjiang were significantly higher than those in Southern Xinjiang.However,the amylose content of both the Wx-B1 e and unknown type 1 in Northern Xinjiang was significantly higher than that in Southern Xinjiang.3.Based on the starch content of 180 Xinjiang spring and winter wheat in landraces and cultivars in the Northern and Southern Xinjiang,some excellent materials were selected.For example,five materials,namely,3896,3898,3903,3908 and 4102,and six materials,viz.DM1840,DM1846,DM1851,DM1851,DM1871 and Kadong No.3 were materials with high(> 77 g/100g)or low total starch content(< 68 g/100g).There were four materials,i.e.3879,DM1929,DM1935 and Badong No.3 and six materials,namely 3969,4001,4082,Xinchun 5,Xinchun 6 and Xinchun 19 were considered as high(>21 g/100g),six as low in amylose content(<17 g/100g).Simliarly,three(3903,3908 and 4102)and two materials(DM1840 and Kedong No.3)were respectively with high(>59 g/100g)and low(<47 g/100g)in amylopectin content.Not expectedly,only one material with high(DM1870,>0.43)and one with low(Xinchun 5,<0.28)in the ratio of amylose/amylopectin were selected.These materials are good candidates for elucidating the genetic of wheat starch content and also provided new germplasms for the genetic improvement of starch related trait of wheat.