苎麻新品种湘苎3号选育及光合作用等特性的研究

 湘苎3号（原名C-20）系广西黑皮蔸经自由授粉的后代中选育而成的。该品种具有光合生产力强，干物质积累速度快，高产、优质、抗病、适应性强等特性。在湖南省多点试验结果，增产15%-38%，全年纤维平均支数达2000支，高抗花叶病。湘苎3号#+(14)C同化物的运转速率和向麻皮的分配率均高于对照品种。光合速率、蒸腾速率、叶导性和水分利用率均显著高于对照品种，而暗呼吸速率只略高于对照。湘苎3号的最大叶面积系数可达7左右，光合速率可达14mgCO#-2·dm#+(-2)h#+(-1)。可见，湘苎3号具有较良好的生理基础。

BREEDING NEW RAMIE VARIETY XIANGZHU 3 AND STUDIES ON ITS CHARACTERS OF PHOTOASSIMILATE METABOLISM

Fiber yield of new variety Xiangzhu 3 (Boehmeria nivea L.) is 15%-38% higher than that of check cuitivars in the variety test of five counties in Hunan province. Its average fiber fineness of three harvests is 1996-2100 counts Its mosaic disease severity index is 4.32, which is obviously lower than that of check cultivars. Its rate of translocation and partition of ~(14)C-labelled assimilate is higher. Moreover, compared with cheek cultivar "Luzhuqing", Xiangzhu 3 is characterized by markedly higher total transpiration, conductance and water use efficiency. These are closely related with photosynthetie rate. It has much higher photosynthetic and a little higher dark respiration rates. Its maximum value of leaf area coefficient rises to 7 approximately, and its photosynthetic rate is about 14 mgCO_2dm~(-2) h~(-1). Because of close relationship between photoassimilate metabolism and fiber yield, the physiological characters stated above may be used as comprehensive index to forecast yield in ramie breeding.