Straighthead and Agronomy Characters Testing for Selected Parent Lines and Hybrid Combinations at UAPB in 2011-2012

Straighthead disease is a physiological disorder in rice and the most widespread non-fungal disease of the U.S. straighthead greatly reduces rice yield. Straighthead studies were most conducted in the artificial field which was Arsenic amendment plots due to the similarity of straighthead symptoms of Arsenic damage. To evaluate the straighthead disease resistance in natural condition, 46 rice lines, including 24 inbred lines and 22 hybrid combinations which were developed from breading program, were chosen for straighthead and agronomy characters testing in a native soil where straighthead naturally induced in the past years at University of Arkansas at Pine Bluff (UAPB), Arkansas in 2011 and 2012. The straighthead of rice were rated from 0 to 9 levels, and 0 was the least straighthead disorder and 9 was the most severe straighthead disorder. Cocodrie (CCDR) was used as the check in this study. The results of 2011 showed that the yields of 8 entries were higher than the check CCDR. The straighthead scores of these 8 entries were 0 - 1 which indicated their resistance to straighthead. The rest of the entries had lower yields than check CCDR with straighthead scores 5 - 6 which indicated their moderate susceptibility to straighthead. The yields were negatively related to the straighthead scores (r = -0.9178, P < 0.01). The results of 2012 showed that the yields of 9 hybrids and 6 inbred entries were higher than the check CCDR. The straighthead scores of top 12 entries were 0 - 2 which indicated that they were resistant to straighthead and 3 entries with straighthead score of 3 which indicated they were moderately resistant to straighthead. The rest 3 hybrids and 4 inbred entries had lower yields than the check and their straighthead scores were 5 - 6 which indicated their moderately susceptible to straighthead. The yields was negatively related to the straighthead scores (r = -0.956, P < 0.01). Compared to CCDR, the yield of hybrids showed their straighthead resistance at some extent. The yields of top six entries, hybrid 33A/PB23, inbred 3053, hybrid 28s/PB22, 28s/PB24, 29s/PB24 and inbred 3222, were 10,376.4, 9991.4, 9566.7, 9334.3, 9183.9 and 9174.3 Kg/Ha, and 46.0%, 40.7%, 34.7%, 31.4%, 29.3%, and 29.5% higher than the check, respectively.

广西崇左地区水稻旱青立病发生的原因及对策

近年来,水稻旱青立病在我国的水稻生产上较为常见,具有受害面积广、影响品质产量较为严重的特点。通过了解、分析旱青立病的发病症状、发病规律、发病成因,提出防治方法以减少旱青立病对水稻的危害。

穗部畸形水稻植株和土壤中矿质元素及砷含量的分布

湖北江汉平原旱改水稻田常常发生水稻(Oryza sativa L.)穗部畸形病。2013年调查分析了旱改水稻田中两个水稻品种(丰两优香1号和糯优1号)穗部畸形和正常植株不同部位及其根际土壤中矿质营养元素和砷的含量。结果表明,发病水稻根际土壤p H及土壤有机质均略低于正常水稻根际。两个水稻品种穗部畸形植株中N、P、Mn和As含量与正常植株相比差异不显著。糯优1号水稻发病植株茎和叶中K、Mg和Cu的含量显著低于正常植株(P<0.05),但丰两优香1号发病植株仅根中Ca的含量显著降低、及显著提高了茎中Cu的含量(P<0.05)。本次调查说明,江汉平原水稻穗部畸形病的发生可能与植株矿质元素含量缺乏或过量无关。

旱改水田水稻旱青立病的发生原因及防治措施研究

水稻旱青立病是危害水稻生产的一种生理性病害,近年在旱改水田中发生较重,对水稻产量的影响很大,但因其发病原因尚不明确,给该病的防治带来一定难度。通过调查湖南省茶陵县旱改水田2020、2021年水稻旱青立病的发生情况,分析了该病的发生原因,并通过田间试验提出了防治的具体措施。结果表明,2020年茶陵县旱改水田水稻旱青立病的发病穗率与发病粒率分别达到了26.42%、26.96%,2021年两项数据也分别达26.30%、24.00%,2020、2021年造成水稻减产分别为25.11%、22.92%。土壤板结严重、透气性差、有机质含量低、长期淹水灌溉是旱改水田该病发生较重的主要原因。通过采用针对性防治措施,包括增施有机肥、施用硫酸钾、撒施生石灰和科学水管理等,水稻旱青立病的发生得到了有效控制,综合治理区该病的病穗率与病粒率分别仅为1.36%、0.72%,而空白对照区分别达26.30%、24.00%。本研究为旱改水田水稻旱青立病的防治提供了重要借鉴。