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Marssonina blotch, caused by the fungus Marssonina coronariae, is a serious foliar disease on apple in East Asia as well as in other moist temperate regions in Asia, Europe, and South America. Several fungicides were investigated for their toxicity to mycelial growth and conidial germination of the pathogen in vitro. Tebuconazole, kresoxim-methyl, hexaconazole, propiconazole, and a mixture of tebuconazole and benziothiazolinone sharply inhibited mycelial growth but had less effect on conidial germination. Field tests were conducted in a commercial orchard in Baishui County, Shaanxi Province, China, during 2012, 2013, 2014, and 2015 in order to develop recommendations for apple growers. Three applications of tebuconazole, hexaconazole, propiconazole, or a mixture of tebuconazole and benziothiazolinone at 20-day intervals from early July to late August resulted in defoliation incidence of <5%. When sprays of Bordeaux mixture + tebuconazole, Bordeaux mixture + propiconazole, and Bordeaux mixture + tebuconazole and benziothiazolinone were alternated, the spray interval was extended to 25 days and defoliation incidence remained <5%. Based on historical records and our results, scouting for symptoms should begin in mid-June. We recommend commencing the spray period in early July in years with normal rainfall patterns, and spraying in mid- to late June in years with much rainfall. The findings of this study create a foundation for implementation of an efficient spray program against Marssonina leaf blotch in apple orchards in the Loess Plateau Region of China.

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A photoperiod/thermo-sensitive male sterile line, named Huiyou50S, was developed from a spontaneous semi-sterile plant found in Brassica napus cultivar Huiyou50. The male sterility of Huiyou50S was controlled by recessive nuclear genes. Huiyou50S presents male sterile under high temperature and long photoperiod condition, and fertility under low temperature and short photoperiod. The cytological characters of pollen and the anther development of Huiyou50S at the different stages were compared with its near isogenic line Huiyou50F, which is the male fertile sibling, by techniques including semi-thin sections, scan electronic microscopy, pollen grains staining with aceto-carmine, and whole anther clearing with methyl salicylate. The result indicated that the anther development of Huiyou50S was similar to that of Huiyou50F from sporogenous cell, pollen mother cell, meiosis, to tetrad stage. At the uni-nucleate stage, although the exine formed, the protoplast of microspores condensed, and the cell became empty. At last all cellular content of pollen degraded completely and only the empty and distorted shell remained. The tapetum development of Huiyou50S was similar to that of Huiyou50F up to tetrad stage, but its tapetal cells rapidly disintegrated at the uni-nucleate stage, which occurred earlier than that in Huiyou50F, while the tapetum of Huiyou50F did not degenerate at this stage. In conclusion, the microspores of Huiyou50S abort mainly at the uni-nucleate stage, and there are some associations between pollen abortion and tapetal cells' disintegration. This result is helpful to classification and utility of photoperiod/thermosensitive genic male sterility.