甘蔗优良新品种(系)抗褐锈病基因Bru1的分子检测及自然抗性评价

甘蔗褐锈病是目前中国蔗区发生最普遍、危害最严重的病害之一,选育和种植抗病品种是防治该病最为经济有效的措施。为明确近年国家甘蔗体系育成的50个新品种(系)对甘蔗褐锈病的抗性,确定其应用潜力,本研究通过在甘蔗褐锈病高发蔗区云南德宏、保山2个区域化试验站,采用田间自然抗性调查与分子标记辅助鉴定抗性基因的方法,于2014年和2015年对中国近年选育的50个优良新品种(系)及2个主栽品种进行抗褐锈病基因Bru1的分子检测及自然抗性评价。田间自然发病调查结果表明,50个优良新品种(系)及2个主栽品种中,高抗至中抗的有34个,占65.38%。其中15个材料表现高抗,占28.85%,16个材料表现抗病,占30.77%,3个材料表现中抗,占5.77%;分子检测结果显示,共29个抗病材料含有抗褐锈病基因Bru1,出现频率为55.77%,表明中国近年选育的优良新品种(系)中抗褐锈病性主要由Bru1控制;其余5个抗病材料均不含抗褐锈病基因Bru1,暗示除了Bru1外,可能还有其他抗褐锈病基因存在。不同系列品种田间感病品种的频率和含抗褐锈病基因Bru1的频率不同,粤糖系列品种感病品种的频率最高达到60%,含Bru1的频率最低,只有30%,抗性最弱;云蔗系列品种感锈病品种的频率最低只有12.5%,含Bru1的频率最高,达到81.25%,抗性最好。本研究结果为深入开展甘蔗抗褐锈病育种,选育和推广优良抗病品种,有效防控甘蔗褐锈病提供了科学依据和优良抗性新品种(系)。

Resistance evaluation to brown rust and molecular detection of Bru1 gene in new elite sugarcane varieties/lines

Sugarcane brown rust is one of the most widespread and destructive diseases in main sugarcane plan-ting areas in China. Breeding and growing resistant cultivars are the most economic and effective measures for controlling this disease. To determine the sugarcane brown rust resistance and their application potential of 50 new elite sugarcane varieties/lines bred from China Sugarcane System in recent years, the linked molecular markers of brown rust resistance gene Bru1 were used to test these 50 varieties/lines using two commercial varieties as control. Meanwhile, the disease resistance to brown rust of these cultivars/lines was investigated and analyzed under natural inoculation at the Comprehensive Experimental Station of the China Sugarcane System in Dehong and Baoshan, where brown rust are frequent and severe, in Yunnan in 2014 and 2015. Field surveys indicated that 34 out of 50 new elite varieties/lines and two control varieties (65.38%) showed highly resistant to moderately resistant. Of these, fifteen (28.85%) were highly resistant, sixteen (30.77%) were resistant and three (5.77%) were moderately resistant. Molecular detection results suggested that Bru1 was present in 29 (55.77%) materials out of the 34 resistant cultivars/lines, indicating that brown rust resistance in new elite sugarcane varieties/lines in China is primarily controlled by Bru1. The absence of Bru1 in the other 5 resistant varieties/lines suggests that they may carry other brown rust resistance-associated genes. The frequencies of susceptible varieties in field and varieties carrying Bru1 gene were different in different series of sugarcane varieties. The resistance of Yuetang series of sugarcane varieties was the weakest which have the highest frequency (60%) of susceptible varieties and the lowest Bru1 frequency (30%); the resistance of Yunzhe series of sugarcane varieties was the best which have the lowest frequency (12.5%) of susceptible varieties and the highest Bru1 frequency (81.25%). These results may facilitate brown rust resistance breeding and provide new elite resistant varieties for sugarcane brown rust effectively control.