芥菜型油菜（B.juncea）杂种优势利用研究：优质强优势杂交油菜的选育

从1986年开始,开展了降低芥酸含量,提高油酸和亚油酸含量,提高抗病性,以杂优利用为中心的优质强优势杂交油菜的选育。育成了自交结实指数在1以下,不育株率100％,芥酸含量0.03-2.51％,亚油酸含量28.30-33.09％的89S181等6个不育系。育成了恢复株率97.92-100％的ZKC和89S016等5个低芥酸恢复系。 在三系配套的基础上,经测交,选育出亩产110.5-185.6公斤的5个强优势组合,组合的芥酸含量0.31-0.64％,亚油酸含量31.06-35.09％。并发现亚油酸含量亦有优势表现,6个F1组合的亚油酸含量,全部高于双亲平均值,有5个组合则超过高亲值。 5个强优势组合都导入了花叶苦菜(蔬菜芥菜)的抗病毒病性状(基因),经冬夏两季自然诱发鉴定,强优组合的发病率都低于邻近对照。优质、抗病、强优组合的选育研究已初告完成,1992年以后将陆续投产使用。     

In Vitro Digestion of RS4‐Type Resistant Wheat and Potato Starches,and Fermentation of Indigestible Fractions

RS4‐type resistant wheat starch (RWS) and resistant potato starch (RPS) were subjected successively to in vitro digestion with pepsin and pancreatin‐bile, and the indigestible residues (82.1% db and 74.1% db, respectively) were recovered and subsequently fermented by in vitro techniques using fresh human fecal microbiota as inoculum. Scanning electron microscopy of the indigestible residues showed surface erosion on the residual granules. Total gas production during the in vitro fermentation increased almost linearly over time with the two resistant starches exhibiting similar gas production rates, as well as a similar rate of production of total short‐chain fatty acids (SCFA). The indigestible fractions from both starches produced acetate as the major SCFA and relatively higher levels of butyrate than propionate, but wheat starch tended to produce more butyrate over time than potato starch. Fractional molar ratios of acetate, propionate, and butyrate from the RWS and RPS were 0.586:0.186:0.228 and 0.577:0.200:0.223, respectively. The calculated caloric contributions of the RWS and RPS are ≈33% lower than for unmodified starch and are comparable to those reported in the literature for RS2 and RS3 high‐amylose maize starches.