黄百香果花粉离体培养基筛选及贮藏试验

【目的】分析不同配方培养基及贮藏条件对大果型黄百香果花粉离体萌发效果的影响,为大果型黄百香果花粉活力鉴定、人工辅助授粉及杂交育种提供理论依据。【方法】采集花瓣刚好完全展开大果型黄百香果花朵的花粉,采用L_(25)(5^(4))正交试验设计,筛选适宜其离体培养的蔗糖、硼酸、硝酸钙浓度及pH;利用最适宜花粉离体培养基,开展花朵不同采样时间、花粉离体贮藏湿度和温度对花粉活力影响试验,确定适宜大果型黄百香果花粉的离体贮藏条件。【结果】正交试验分析结果表明,影响大果型黄百香果花粉萌发率的因素排序为硝酸钙>蔗糖>硼酸>pH,确定花粉离体萌发的最适培养基为100.00 g/L蔗糖+0.02 g/L硼酸+0.40 g/L硝酸钙,培养基pH 5.0。在最适培养基中,大果型黄百香果花粉的萌发率为85.55%;于11:30—17:30采集大果型黄百香果花粉的萌发率均在80.00%以上,其中,开花后3 h(16:30)花粉的活力最强,显著高于除13:30和15:30外的其他时间采集花粉的萌发率(P<0.05,下同)。花粉贮藏试验结果表明,平铺在硫磺纸上自然风干处理3~48 h的花粉萌发率均显著高于同时间段密封于离心管中常温贮藏和平铺在硫磺纸上置于干燥器中贮藏处理,其中在硫磺纸上自然风干贮藏48 h的花粉萌发率仍达34.28%;自然风干5 h后密封于离心管中4℃贮藏24 h的花粉萌发率为61.49%,显著高于自然风干5 h后密封于离心管中-20℃贮藏24 h的花粉萌发率(55.22%)。【结论】大果型黄百香果花粉离体萌发最适培养基为100.00 g/L蔗糖+0.02 g/L硼酸+0.40 g/L硝酸钙及pH 5.0;当天采集花朵的花粉自然风干5 h后密封于离心管4℃贮藏其萌发效果最佳。

播期对机插杂交籼稻不同茎蘖部位稻穗枝梗数和颖花数的影响

为探究播期对机插杂交籼稻不同茎蘖部位稻穗枝梗数和颖花数的影响,以穗型差异较大的杂交籼稻品种F优498和宜香优2115为材料,通过分期播种试验研究机插杂交籼稻不同播期下不同茎蘖部位稻穗的枝梗数和颖花数。结果表明,(1)每穗一次、二次颖花数及二次枝梗数为:主茎>一次分蘖>二次分蘖,主茎和一次分蘖的一次、二次颖花数及二次枝梗数随播期推迟呈增加趋势,且平均一次、二次颖花数及二次枝梗数也随播期推迟而增加。每穗总枝梗数及总颖花数表现出了相同趋势。平均每穗总枝梗数和总颖花数也随播期推迟呈增加趋势。(2)相关分析表明,主茎、一次分蘖和二次分蘖的每穗总枝梗数及总颖花数与平均每穗总枝梗数及总颖花数呈极显著正相关,相关系数表现为主茎>一次分蘖>二次分蘖,且通径分析表明,主茎和一次分蘖的每穗总枝梗数及总颖花数对平均每穗总枝梗数及总颖花数的贡献率远大于二次分蘖。(3)主茎、一次分蘖和平均每穗大部分枝梗及颖花性状与穗分化期最高温度、平均温度和平均日照时数呈显著或极显著的正相关。综合看来,不同播期下主茎、一次分蘖和二次分蘖的枝梗数和颖花数有较大差异,选择大穗型籼稻品种进行机插更有利于获得较高的稻穗枝梗数和颖花数,同时根据播期确定相应的高产策略,早播机插在保证较高一次分蘖数的基础上,应注重提高每穗枝梗数和颖花数以提高产量,迟播机插在保证较高每穗颖花数的基础上,应注重提高结实率、千粒重。

2017年广西香蕉行情低迷的原因分析及对策建议

结合全国和广西香蕉种植概况,针对2017年崇左市的香蕉种植、产销及枯萎病发病情况开展深入调研。结果表明:2011—2016年广西香蕉种植面积(增幅26.32%)和总产量(增幅55.50%)整体呈上升趋势,但2017年广西香蕉种植面积缩减,形势严峻;2017年崇左市香蕉产业面临蕉园改种、品质下降、供过于求、价格不稳定以及持续低价和种植户抵御市场风险能力较弱等问题。此外,2017年广西南宁、钦州等香蕉主产区香蕉枯萎病蔓延迅速,全区重病区蕉园改种普遍。广西香蕉行情低迷的原因主要为:香蕉集中上市,供过于求,普遍增产加剧供求矛盾,品质下降影响贮藏和销售;进口蕉占据重要市场;大众的水果消费结构发生变化。从产业技术、产业发展、国际贸易及临时应对措施方面提出了应对对策和建议。

Indica rice restorer lines with large sink potential exhibit improved nutrient transportation to the panicle,which enhances both yield and nitrogen-use efficiency

The yield and nitrogen use efficiency(NUE)of hybrid rice combinations are closely related to restorer line.Therefore,it is essential to evaluate the agronomic characteristics of restorer lines with high yield and high NUE(HYHN).However,it is unclear which restorer lines are HYHN,and neither have the common agronomic traits of the HYHN restorer lines been identified.Aiming to address this issue,we conducted two filed experiments using three nitrogen applications,which screened five HYHN restorer lines from 15 indica restorer lines.Yield,NUE and nutrient transportation of restorer lines with different yields and NUE types were examined.Yield and total nitrogen absorption in aboveground biomass(TNA)increased,whereas NUE for grain production decreased with increasing nitrogen application levels.The HYHN restorer lines had large spikelets and high weight per panicle that were significantly positively correlated with yield and NUE.Therefore,large sink potential may be beneficial for both yield and NUE.We further studied the differences in nutrient transportation to panicles between the HYHN and low yield and low NUE(LYLN)restorer lines and found that the former had a higher nitrogen absorption level and dry matter weight ratios of panicle in maturity.Moreover,the HYHN lines also had a higher root and neck-panicle node bleeding intensity per stem after heading and more developed vascular bundles of neck-panicle nodes and leaves than the LYLN lines,which could contribute to the transportation of nutrients from root to ground and from stem and leaf to spike.Therefore,the advantages of large sink potential of the HYHN restorer lines include large nutrient accumulation in and distribution to the panicles and smooth flow of nutrients along the transportation channels.

施用镁硼锌肥对香蕉生长及果实产量和品质的影响

[目的]探究施用镁、硼、锌肥对香蕉植株生长及果实产量和品质的影响。[方法]试验设NPK、NPKMg、NPKB、NPKZn和NPKMgBZn5个处理,各处理3次重复,试验小区按随机区组排列,连续观测3年。[结果]施用镁、硼、锌肥通过促进香蕉植株的生长,增加香蕉的果指数、果指长和果指粗,提高香蕉果实的单果重,从而显著提高香蕉的产量,并且改善果实的品质。在施用氮磷钾肥的基础上同时配合施用镁、硼和锌肥可增加香蕉果实产量11.61%,维生素C、可溶性糖和还原糖含量分别提高了13.4%、5.4%和8.8%。[结论]施用镁、硼、锌肥可显著提高香蕉的产量及果实的可溶性糖、还原糖和维生素C含量,建议在施用氮磷钾肥的基础上,同时配合施用镁、硼和锌肥比单独施用镁肥、硼肥、锌肥的效果更好。

Growth characteristics and grain yield of machine-transplanted medium indica hybrid rice with high daily yield

High-yield rice varieties with a suitable growth duration are required for mechanical transplanting in multiple cropping systems. Daily yield is an appropriate criterion for the selection of machine-transplanted rice varieties. The aim of this study was to investigate the growth characteristics and grain production in machine-transplanted medium indica hybrid rice with a high daily yield. We conducted a field experiment on 20 medium indica hybrid rice varieties in 2017 and 2018.Grain yield decreased significantly with growth duration between jointing and heading, but it increased with dry matter accumulation, growth rate between jointing and heading, dry matter partitioning to the stem plus sheath at heading, daily yield, and number of spikelets per panicle. Compared with the medium and low daily yield variety types, the high daily yield variety type increased shoot biomass by improving crop growth rate and dry matter accumulation amount between jointing and heading and after heading. The high daily yield variety type decreased the growth duration pre-heading and the proportions of dry matter partitioned to the leaf lamina at heading and maturity, but it also increased the post-heading accumulated dry matter in the grain and the remobilization of dry matter stored in the vegetative organs. Furthermore,the high daily yield variety type significantly increased the occurrence rate of tillers, which is beneficial for the formation of a larger panicle size and an increase in the grain-filling rate. These changes contributed to a 6.51–23.16% relative increase in grain yield of the high daily yield variety type. In conclusion, the selection of high daily yield indica hybrid rice varieties with shorter pre-heading growth duration, greater tiller occurrence rate and spikelet numbers per panicle, higher post-jointing growth rates and stem plus sheath dry matter accumulation at heading is suitable for machine-transplanted rice.

广西地区西番莲产量和品质形成特征及其对气象因子的响应

为探明广西地区西番莲的产量和品质形成特征及对气象因子的响应,以国内主栽西番莲品种‘台农1号’为试验材料,调查测定其产量和产量构成以及同期成熟的各级枝蔓果实品质和同级枝蔓在不同时段成熟的果实品质,采用相关分析和回归分析统计方法研究果实品质性状与开花到成熟期气象因子的关系。结果表明:‘台农1号’西番莲的单位面积产量为11.65 t·hm^(-2),二级蔓和一级蔓占单株产量的比例分别为58.2%和24.2%,是产量构成的主要枝蔓;果实的收获时段为移栽后91~186 d,果实成熟时间范围较大,为43~165 d,但果实形态和单果重受成熟时间的影响不大;同时期收获的各级枝蔓间品质差异主要在果浆重、可滴定酸含量和果皮厚度;同级枝蔓不同生长季收获的果实品质中,果浆重、出汁率随生长季延后和成熟时间的增加而增加,但当成熟时间大于125.6和141.6 d后,果浆重和出汁率分别开始下降;而可溶性固形物含量和果皮厚度则从次年1月开始呈下降趋势;除最大相对湿度外,果实发育到成熟期的温度和光照强度均与果浆重和出汁率呈极显著负相关,而相对湿度与其呈极显著正相关。当果实开花到成熟期的日平均温度为16.1~18.7℃、日平均光照强度为2.8×10^(3)~3.2×10^(3)lx、日平均相对湿度为88.0%~89.4%时,‘台农1号’的果浆重(>35 g)和出汁率(>45%)均较易获得高值。