Measurement and management of genotype-environment interaction (GxE) for the improvement of rainfed lowland rice yield in Cambodia

The magnitude and nature of genotype-by-environment interactions (G×E) for grain yield (GY) and days to flower (DTF) in Cambodia were examined using a random population of 34 genotypes taken from the Cambodian rice improvement program. These genotypes were evaluated in multi-environment trials (MET) conducted across three years (2000 to 2002) and eight locations in the rainfed lowlands. The G×E interaction was partitioned into components attributed to genotype-by-location (G×L), genotype-by-year (G×Y) and genotype-by-location-by-year (G×L×Y) interactions. The G×L×Y interaction was the largest component of variance for GY. The G×L interaction was also significant and comparable in size to the genotypic component (G). The G×Y interaction was small and non significant. A major factor contributing to the large G×L×Y interactions for GY was the genotypic variation for DTF in combination with environmental variation for the timing and intensity of drought. Some of the interactions for GY associated with timing of plant development and exposure to drought were repeatable across the environments enabling the identification of three-target populations of environments (TPE) for consideration in the breeding program. Four genotypes were selected for wide adaptation in the rainfed lowlands in Cambodia.

Contribution of potential yield, drought tolerance and escape to adaptation of 15 rice varieties in rainfed lowlands in Cambodia

In Cambodia, grain yield in rainfed lowland rice is often affected by drought during late vegetative or reproductive stage. Several experiments were conducted to quantify the contribution of potential yield, drought tolerance and drought escape mechanisms to yield under water stress conditions. In total nine pairs of well irrigated and simulated drought (by draining water) experiments were conducted. Potential yield was obtained under irrigation. Grain yields and flowering dates were recorded in 15 varieties. Drought tolerance was quantified by using drought response index (DRI), which is grain yield under drought adjusted for potential yield and flowering date of the variety. Drought escape is expressed as days to flower under drought conditions. Mean yield reduction due to drought of nine experiments was 27 % (range 12-44). The relative contribution of yield potential, flowering date and DRI to observe yield under drought were evaluated by multiple regression for each experiment. Potential yield accounted for 54% (with a range of 10-80) of the variation in actual yield under drought. This was followed by DRI and flowering date with 34 (with a range of 0-60) and 12 (with a range of 0-30) of the contribution, respectively. It is concluded that selecting for drought tolerance as well as for high yield potential would be important in developing cultivars for rainfed lowlands in Cambodia. Although flowering dates are important for drought escape, it had a small contribution probably because drought developed slowly in these experiments in Cambodia.

Women are silver, women are diamonds: Conflicting images of women in the Cambodian print

This paper examines 116 articles related to sexual and reproductive health translated into English from the Khmer press from April 1997 to February 2004. These excerpts were found in The Mirror, a publication of the non-governmental organisation Open Forum of Cambodia, which collates Grid reviews all issues of the Khmer press on a weekly basis. Five major themes were identified: the politics of women's health, government regulation and control, the sex industry in Cambodia, rape, and the HIV epidemic. Discourse analysis of these articles in the context of other sources and experience allows a gendered exploration of the reporting of sexual and reproductive health and rights issues in Cambodia by the Khmer print media. The reports explore the contested political empowerment of women in this strongly hierarchical society, and the mechanisms used to regulate and control sexual activity. The expanding sex industry and associated sexual trafficking ore reported, together with the corruption of legal structures designed to regulate health systems and protect women and children from sexual exploitation and rope. The growing problem of AIDS and successes in reducing HIV transmission through the collaboration of sex workers in the 100% condom use policy is documented, and the tensions implicit in G Cultural representation of women that both protects and constrains women ore explored. (C) 2004 Reproductive Health Matters. All rights reserved.