Double rice-cropping areas in the dry and wet seasons have been increasing in Myanmar, and hybrid rice has been cultivated throughout the country. However, weeds are often not adequately managed. Therefore, the objective of this study was to investigate the effect of weed infestation on rice production of three hybrid varieties (Palethwe 1, Palethwe 3, and Palethwe Basmati) and three inbred varieties (Manaw Thu Kha, Shwe Thwe Yin, and Sin Thwe Latt) in the dry and wet seasons in a lowland rice field. In the dry and wet seasons, 19 - 20 weed species were naturally infested into the fields. Limnocharis flava was the most abundant weed in both seasons. Weed dry weight and rice grain yield showed a negative linear relationship in both seasons. Manaw Thu Kha showed the highest yield loss in the un-weeded fields in both seasons, while Sin Thwe Latt and Palethwe Basmati showed the lowest yield loss in the dry season and wet season, respectively. Sin Thwe Latt recorded the lowest yield loss of 30.21% on average in both seasons, and the highest yield loss of 60.37% was recorded for Manaw Thu Kha. The average rice grain yield loss of all the varieties in the un-weeded fields was 64.37 and 33.66% for the dry and wet seasons, respectively. Thus, the yield loss in the dry season was 1.9-times greater than that in the wet season. The present research suggests that adequate weed management is necessary for rice cultivation, especially in the dry season in Myanmar.

中文翻译：

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杂草侵染对缅甸杂交和自交水稻品种生产力的影响

缅甸旱季和雨季双季稻种植面积不断增加，全国各地都种植了杂交水稻。然而，杂草往往没有得到充分的管理。因此，本研究的目的是调查杂草侵染对三个杂交品种（Palethwe 1、Palethwe 3 和 Palethwe Basmati）和三个自交品种（Manaw Thu Kha、Shwe Thwe Yin 和 Sin Thwe Latt）水稻产量的影响。 ) 在低地稻田的旱季和雨季。在旱季和雨季，有19-20种杂草自然侵入田间。黄蚯蚓是两个季节中最丰富的杂草。杂草干重与水稻产量在两个季节均呈负线性关系。Manaw Thu Kha 在两个季节的未除草田中的产量损失最高，而 Sin Thwe Latt 和 Palethwe Basmati 分别在旱季和雨季的产量损失最低。Sin Thwe Latt 两个季节的平均单产损失最低，为 30.21%，而 Manaw Thu Kha 的单产损失最高，为 60.37%。旱季和雨季未除草田所有品种的稻谷平均产量损失分别为64.37%和33.66%。因此，旱季的产量损失是雨季的 1.9 倍。目前的研究表明，水稻种植需要适当的杂草管理，尤其是在缅甸的旱季。