甘蔗与斑茅割手密复合体的回交后代真实性鉴定及染色体遗传分析

摘要

【目的】掌握斑茅割手密复合体（简称斑割复合体）在杂交利用过程中的染色体遗传规律，为斑割复合体适宜回交利用代数提供参考依据。【方法】选用4对引物对甘蔗与斑茅割手密复合体的回交后代进行SSR标记鉴定，并利用甘蔗根尖细胞酶解去壁低渗法对真实杂种进行染色体数目观察。【结果】供试的28个杂交后代材料（15个GT05-164与GXASF108-2-28杂交BC1代，13个GT42与GXASBC112-A6-25杂交BC2代）均为真实杂种。选择在2对SSR引物中均扩增出父本特征带的后代（5个BC1代和7个BC2代）进行染色体观察，结果发现，5个BC1代的染色体数目介于95~98条，其染色体按“n+n”方式传递；7个BC2代的染色体数目介于94~101条，其染色体也按“n+n”方式传递。【结论】甘蔗与斑割复合体杂交BC1和BC2代中染色体传递方式均为“n+n”，母本甘蔗的染色体未加倍，高贵化育种进程减慢，可能需要更高的杂交代数才能获得聚集斑茅和割手密血缘的优良品种（系）。%Objective]Inheritance of chromosome was studied in the process of hybridization between sugarcane(Saccha-rum officinarum) and intergeneric hybrid complex(Erianthus arundinaceus × Saccharum spontaneum) to lay a good founda-tion for exploration of optimum backcross generations. [Method]The backcross progenies from sugarcane (S. officinarum) and intergeneric hybrid (E. arundinaceus×S. spontaneum) were identified with four pairs of SSR primers and chromo-some number for the hybrids was calculated by means of cell wall degradation hypotonic smear method. [Result]All 28 progenies, 15 BC1 progenies from GT05-164 and GXASF108-2-28 and 13 BC2 progenies from GT42 and GXASBC112-A6-25, were confirmed as hybrids. Chromosome numbers of progenies(five BC1 hybrids and seven BC2 hybrids) in which am-plification of paternal characteristics band occurred in two pairs of SSR primers were observed. The somatic chromosome num-bers of five BC1 hybrids and seven BC2 hybrids were 95-98 and 94-101, respectively, all following the law of n+n. [Conclu-sion]Chromosome transmission in BC1 and BC2 hybrids of backcross progeny from sugarcane and intergeneric hybrid follows n+n mode. Chromosome numbers female parent sugarcane(S. officinarum) are not doubled, and nobilisation progress slows down. More generations may be needed to obtain superior varieties(lines) of E. arundinaceus and S. spontaneum consanguinity.