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This review discusses the results of previous and current research on breeding for disease resistance in aquaculture with special reference to shrimp and tilapia breeding programs in Egypt. Disease prevention strategies such as elimination, eradication, and cultural control proved to be ineffective, costly, and unsustainable. Selective breeding offers a long-term sustainable disease control by improving genetics of disease resistance. Disease resistance has proved to be heritable trait; there are a number of applied breeding programs designed in several countries to select for improved disease resistance. Thus, Egypt has designed and implemented two breeding programs for genetic improvement of disease resistance in Indian white shrimp (Fenneropenaeus indicus) and red tilapia in late 2014 and early 2015, respectively. The objectives were to genetically improve disease resistance in red tilapia and develop a microsatellite-based genotyping system for F. indicus resistant to diseases for commercial aquaculture in Egypt. [ABSTRACT FROM AUTHOR]

This article examines the economic consequences of widowhood and the possibility of maintaining female-managed farms in a predominantly male world. A unique dataset is exploited to investigate the productivity of female-headed households in preindustrial Sweden. The main source material is tithe payment rolls maintained by parish priests, which reflect fluctuations and long-term trends in the annual economic output of more than 2,000 individual farms. No evidence was found that farm management conducted by widows was dissolved by male relatives or neighbours. Farm management by widows was in many cases a temporary arrangement, especially on manorial land, where landlords did not accept female farmers. But among freeholders and crown tenants, widows often refrained from remarriage and continued as farm heads. As for production, farms managed by widows performed slightly better than farms managed by men during the first few years after a takeover. This result levelled out over time and farms managed by long-term widows show production results almost equal to farms run by men. [ABSTRACT FROM AUTHOR]