Reaction of Rice Varieties and Strains to Blast in the Uniform Blast Nursery

Abstract

A total of 161 varieties, selections, and lines were tested for reaction to com-posites of races of the blast fungus in the uniform blast nursery of the Chiayi Agricultural Experiment Station during the 9-year period, 1956-1964. Forty out of 161 entries were found to have similar or higher resistance to leaf blast than the resistant check variety, Chianung 242. Among these, 5 were highly resistant, 25 resistant, and 10 moderately resistant. Only 3 commercial varieties were resistant while the other 19 varieties were susceptible to leaf blast. Twenty nine out of 33 entries resistant to leaf blast were also resistant to neck blast and the remaining 3 were susceptible. Among 21 commercial varieties, 12 resistant and 9 susceptible entries were recorded for neck blast infection. In a large number of varieties and lines, the agreement between leaf and neck reactions was found to be generally good, although in certain entries, a lack of agreement was observed. A number of varieties and selections are resistant to leaf blast and are available for further rice breeding work. Chianung 242, a parent of many resistant select-ions, appeared to be an important source of resistance. 嘉義農業試驗分所稻熱病統一病圃，自民國45年至53年，9年之間先後檢定水稻品種及新育成品系計161種，其中有40個品種（系）之葉稻熱病抵抗性，較抗病對照品種嘉農242號為佳，屬於極抗者5種，屬抗者有25種，中抗者有10種。本省現有主要推廣品種，經本分所檢定者有22個品種，但抗葉稻熱病者僅有3品種，餘外19品種均屬感病。 33個抗葉稻熱病品種（系）中，有29個品種（系）亦可抗穗稻熱病，其餘3品種（系）即屬感病。21個推廣品種中抗穗稻熱病者有12個品種，另9個為感病品種，由此概見水稻品種（系）對葉及穗稻熱病之反應大致相同。由檢定結果透露，凡具有高度抗稻熱病之品種（系），均可供為今後抗病育種之材料。抗病品種嘉農242號已普遍被採用為雜交親本，自其雜交後代育成之抗病系統頗多，堪稱為一重要抗病來源。