Genetic Analysis Of Chromosome And Identification Of Quality And Resistance For The Hybrid And Backcross Progenies Of Saccharum Officinarum And Erianthus Arundinaceus

Erianthus arundinaceus,with many outstanding traits such as drought tolerance,disease resistance and superiority adaptability,is a related genera plant of Saccharum L.It is also a promising germplasm for sugarcane breeding.There is abundant germplasm of E. Arundinaceus in China.In order to make better utilization the germplasm,we carried out the experiments of the calculation of chromosome number,karyotype analysis and ITS marker for hybrid,identification of drought tolerance and disease resistance and sucrose content analysis on the BC₁ and BC₂ of S.officinarum L.and E.Arundinaceus.The results of ITS marker showed that the bands,with sizes of 250～500bp by two primer combinations of EF₁/ER₁ and EF₂/ER₂,specific to E.arundinaceus was observed in six genotypes of YC01-69,YC01 - 134,YC01-116,YC01-36,YC03-06 and YC05-179.It suggests that all of them were genuine progenies of E.arundinaceus and S.officinarum.Some differences were observed in YC01-21 when amplified by primer combinations of EF₁/ER₁ and EF₂/ER₂.For EF₁ER₁,the specific band was observed but not for EF₂/ER₂.YC 01-21 was at last identified as the progeny of E.arundinaceus by karyotypes analysis.The results of chromosome number calculation and karyotype analysis show that the somatic chromosomes number of Neijiang57-416 is 2n= 110=98m+12sm and belongs to 2B type,Ya01-69 is 2n=94=94m and belongs to 1B type,Ya01-134 is 2n=114=114m and belongs to 1B type,Ya01-116 is 2n=92=90m+2sm and belongs to 1B type,Ya01-21 is 2n=104=100m+4sm(4SAT)and belongs to 2C type,Ya01-36 is 2n=132=130m+2sm and belongs to 1B type,Ya03-06 is 2n= 108= 106m+2sm and belongs to 2B type,Ya05-179 is 2n =110=110m and belongs to 1B type.The progenies BC₁ and BC₂ of E.arundinaceum and S. officinarum always follow the chromosome genetic law of n+n,only one of the progenies of E. arundinaceum and S.officinarum named YC01-36 follows 2n+n and the phenomena of 'not balance' chromosome pairing being observed.The responses of photosynthetic parameters to drought stress are divided into three phases and difference in reaction time for difference genotypes.The reactions include stoma close up, less co₂ taking and photosynthesis ability decrease under drought stress.In the same condition, photosynthesis parameters of Pn,Tr,Gs and Ci for one of the progenies of E.arundinaceum YC96-40 are highest in all tested genotypes including its parents and the other progenies.And the change of these four parameters appeared the similar trends.It indicates the decrease of Pn is mainly due to the close up of stoma.It suggests YC96-40 with strong drought tolerance. Under the serious drought stress,Badila and YC01-03 increased greatly in the content of MDA and plasma membrane permeability(PMP)compared to the other genotypes.The smaller increment in the contents of MDA and PMP were observed in HN105,HN92-77 and YC96-66,one of F₁ material of E.arundinaceum.The increments of MDA and PMP in YC01-21 and YC96-40 were less than or equal to CP84-1198.It suggests E.arundinaceum and its progenies have a strong drought tolerance,but not all hybrid progenies will inherit this character.YC96-66,YC01—36,YC96-40 and YC01-21 are highly resistant to sugarcane smut caused by Ustilago scitaminea Syd.This suggests that smut resistance for E.arundinaceum can transmitted to its progenies.Thus,E.arundinaceum will be an important resistance source in sugarcane breeding.Low sucrose content is observed in E.arundinaceum and its F₁ hybrids, but it can be significantly improved by backcross modification.The heredity of sucrose content character appears to be near mid-parent heredity.It may be related to the mode of chromosome heredity.