McCorkle Kestrel, Lewis Ramsey, Shew David
Department of Plant Pathology.
Department of Crop Science.
Plant Dis. 2013 Feb;97(2):252-258. doi: 10.1094/PDIS-05-12-0480-RE.
Black shank, caused by Phytophthora nicotianae, is managed primarily by host resistance. The rapid emergence of race 1 eliminated the usefulness of available complete resistance, leading breeders to search for new sources of resistance. Cigar tobacco 'Beinhart 1000' (BH) is highly resistant to all races of P. nicotianae. Doubled-haploid (DH) lines from a cross of BH and the susceptible 'Hicks' were evaluated for black shank resistance, and quantitative trait loci (QTL) on linkage groups (LGs) 4 and 8 accounted for >43% of the phenotypic variation in resistance. Forty-three DH lines and parents were evaluated, and genotypes with one or both QTL from BH on LGs 4 and 8 had increased incubation periods and decreased root rot but higher final inoculum levels than genotypes with neither QTL. A low level of stem resistance was observed in BH and DH lines with the QTL from BH on LG 4 but not LG 8. Low levels of leaf resistance were seen for Hicks, BH, and DH lines with both QTL from BH on LG 4 and 8. The partial resistance from BH has not been used commercially and may provide an increase in level of partial resistance in future tobacco varieties.
由烟草疫霉引起的黑胫病主要通过寄主抗性来防治。1号生理小种的迅速出现使现有的完全抗性丧失了作用，促使育种者寻找新的抗性来源。雪茄烟品种“Beinhart 1000”（BH）对烟草疫霉的所有生理小种都具有高度抗性。对BH与感病品种“Hicks”杂交产生的双单倍体（DH）系进行了黑胫病抗性评估，4号和8号连锁群上的数量性状位点（QTL）解释了抗性表型变异的43%以上。对43个DH系和亲本进行了评估，在4号和8号连锁群上携带来自BH的一个或两个QTL的基因型，其潜伏期延长，根腐病减轻，但最终接种体水平高于不携带QTL的基因型。在4号连锁群而非8号连锁群上携带来自BH的QTL的BH和DH系中观察到较低水平的茎抗性。在4号和8号连锁群上都携带来自BH的两个QTL的Hicks、BH和DH系中观察到较低水平的叶抗性。来自BH的部分抗性尚未在商业上应用，可能会提高未来烟草品种的部分抗性水平。
