Upland rice varieties for smallholder farming in the cold conditions in Madagascar's tropical highlands
Upland rice varieties for smallholder farming in the cold conditions in Madagascar's tropical highlands
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适用于马达加斯加热带高地寒冷条件下小农耕作的旱稻品种
DOI：
10.1016/j.fcr.2014.09.006
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发表时间：
2014
影响因子：
5.8
通讯作者：
J. Dusserre
中科院分区：
文献类型：
--
作者：
L. Raboin;T. Randriambololona;T. Radanielina;Alain Ramanantsoanirina;N. Ahmadi;J. Dusserre
旱稻种植已成为马达加斯加中部高地景观的常见组成部分，该地区人口稠密，主要特点是资源匮乏的家庭农民和寒冷的气候条件。 2011-2012年对485名农民进行的调查显示，尽管在1995年发布第一个耐寒品种之前该地区还没有种植旱稻，但其中71%的农民种植了旱稻。调查还显示，来自尼泊尔并于2006年发布的单一品种Chhomrong Dhan (CD)是迄今为止种植最广泛的品种，占旱稻总面积的82.5%。农民欣赏 CD 在低投入条件下相对较高的产量。然而，这种主导地位引起了人们对旱稻农业系统面对气候条件或病原体种群变化的恢复能力的担忧。为了确定在这种情况下育种新旱稻品种时应考虑的关键品种适应性特征，我们比较了包括 CD 在内的一组改良品种，在两个种植季节的低投入管理下。收获前叶面积指数（LAI）与产量之间存在很强的正相关关系。产量最高的品种（包括 CD）寿命长、生物量产量高、LAI 高和收获指数最高。水稻品种的 LAI 与杂草的 LAI 之间存在显着的负相关，这表明高 LAI 也有助于限制杂草对资源的竞争。在自给家庭农业和马达加斯加热带高地的寒冷条件下，新的改良品种应结合高LAI、高收获指数和长持续时间，因为这些性状一方面有助于与杂草竞争并有助于在低投入管理下实现高产潜力，另一方面还应具有抗稻瘟病、耐寒性和缩短作物持续时间等防止产量损失的性状。必须考虑作物持续时间和马达加斯加高地寒冷条件特有的寒冷引起的不育风险之间的权衡。
Upland rice cropping has become a familiar part of the landscape in Madagascar's central highlands, a densely populated region mainly characterized by resource poor family farmers and cold climatic conditions. A survey of 485 farmers conducted in 2011–2012 revealed that 71% of them cultivated upland rice although the crop was absent in this region before the first cold tolerant varieties were released in 1995. It also revealed that a single variety, Chhomrong Dhan (CD) originating from Nepal and released in 2006 was by far the most widely cultivated variety and accounted for 82.5% of the total acreage of upland rice. Farmers appreciate CD for its relatively high yield under low input conditions. However, this dominance raises concerns about the resilience of upland rice agro-systems in the face of changes in climatic conditions or in pathogen populations. To identify key varietal adaptive traits that should be taken into account in the breeding of new upland rice varieties in this context, we compared a panel of improved varieties including CD under low input management over two cropping seasons. A strong positive correlation between leaf area index (LAI) before harvest and yield was observed. Varieties with the highest yield, including CD, are of long duration, produce high biomass yields, have a high LAI and the highest harvest index. A significant negative correlation was observed between the LAI of rice varieties and that of weeds, showing that a high LAI also helps limit competition for resources by weeds. In the context of subsistence family farming and in the cold conditions of Madagascar's tropical highlands, new improved varieties should combine high LAI, high harvest index and long duration, as these traits help compete with weeds and contribute to high yield potential under low input management, on the one hand, and resistance to blast, cold tolerance and reduced crop duration, traits that prevent yield losses, on the other hand. The trade-off between crop duration and the risk of cold-induced sterility specific to the cold conditions of Madagascar highlands has to be taken into account.