文摘
Puccinia helianthi Schw. causes sunflower (Helianthus annuus L.) rust in many sunflower production regions in China. To study the virulence pattern of P. helianthi physiological races and evaluate the resistance of major sunflower hybrids and varieties to this pathogen, field surveys were undertaken in 33 counties across major sunflower production regions in China in 2013鈥?014. Eighty rust single-pustule isolates were obtained from 80 geographically different locations. Using a set of nine internationally adopted differentials, 15 races were identified among these isolates. Race 304 was the most prevalent one with a 28 % frequency, followed by races 300 and 310 each with a frequency of 18 %, and the other 12 races (314, 324, 330, 332, 334, 350, 354, 374, 500, 526, 736 and 737) with a frequency varying from 1 to 6 %. The less virulent race group 300 accounted for the largest proportion (87 %) of the collected isolates while the most virulent race group 700 accounted only 4 %. Spores of race 304 and 737 were used to test 69 hybrids and five open-pollinated varieties of sunflower plants collected from breeding programs and local markets. Among the 31 confectionary hybrids, six were immune, two were highly resistant, and 11 were resistant to race 304. Among the 38 oilseed hybrids, eight showed immune reactions, three were highly resistant, and 17 were resistant to race 304. All five open-pollinated varieties were susceptible to race 304. For race 737, only four of the entries showed resistant reactions, and none were confectionary sunflowers. Keywords Puccinia helianthi Schw. Physiological races Sunflower Resistance evaluation