破损青黄贮裹包饲料内部温度动态研究

为了实现对青黄贮裹包饲料有氧变质的风险预测,针对破损青黄贮裹包饲料内部温度变化问题,以青黄贮黑麦草及青黄贮苜蓿为对象展开了研究。设计了特定的贯入仪,在不引入空气的情况下将温度传感器植入裹包饲料内,实现了监测裹包内特定位置温度变化的可操作化。采用两种方案分别对黑麦草裹包饲料与苜蓿裹包饲料内特定位置的温度进行监测,发现在裹包破损后,距离裹包破损口越近的饲料发生温升越早;对裹包内上部与下部相对应的温度检测值进行配对t检验,试验结果表明,破损裹包内与破损口距离相等但分处在裹包上部与下部对称的两点温升过程具有显著差异;分别对不同干物质含量的青黄贮苜蓿与黑麦草裹包饲料温升曲线进行对比,干物质含量较高的青黄贮裹包饲料较干物质含量低的温升快。制定了裹包内温度场分布数据的获取方案,并实现了温度场的可视化。     

Phenotyping of productivity and resilience in sweetpotato under water stress through UAV-based multispectral and thermal imagery in Mozambique

Sweetpotato is a crucial crop to guarantee food security in sub-Saharan Africa, and drought events are considered one of the most critical factors affecting sweetpotato productivity in this region. In this study, airborne imagery based on reflectance (NDVI, CI_red-edge) and canopy temperature minus air temperature (dT) indices was used to characterize sweetpotato genotypes under drought treatments in Mozambique. Two field experiments established in rainy/hot (Trial A) and dry/cool (Trial B) seasons were assessed. In Trial A, 24 genotypes were subjected to early- (ESD), mid- (MSD) and late-season (LSD) drought stress treatments and compared against a control. In Trial B, 120 genotypes were subjected to LSD only. The percentage of reduction in vine weight (PR_VW) under drought was related primarily to temporal variation of NDVI and CI, regardless of drought treatment and seasons. dT in relation to control (dT_Amp) was associated with PR_VW in ESD-Trial A and LSD-Trial B, whereas under LSD-Trial A, dT_Amp was related to total fresh storage root weight (TRW). During the rainy/hot season, higher TRW reduction was promoted under ESD; however, under LSD, it was possible to identify productive genotypes able to withstand drought stress, highlighting their relevance for drought-tolerance selection purposes.     

Dissection of a major QTL for seed colour and fibre content in Brassica napus reveals colocalization with candidate genes for phenylpropanoid biosynthesis and flavonoid deposition

A major quantitative trait locus (QTL) influencing seed fibre and colour in Brassica napus was dissected by marker saturation in a doubled haploid (DH) population from the black‐seeded oilseed rape line ‘Express 617’ crossed with a yellow‐seeded B. napus line, ‘1012–98’. The marker at the peak of a sub‐QTL with a strong effect on both seed colour and acid detergent lignin content lay only 4 kb away from a Brassica (H+)‐ATPase gene orthologous to the transparent testa gene AHA10. Near the peak of a second sub‐QTL, we mapped a copy of the key phenylpropanoid biosynthesis gene cinnamyl alcohol dehydrogenase, while another key phenylpropanoid biosynthesis gene, cinnamoyl co‐a reductase 1, was found nearby. In a cross between ‘Express 617’ and another dark‐seeded parent, ‘V8’, Bna.CCR1 was localized in silico near the peak of a corresponding seed fibre QTL, whereas in this case Bna.CAD2/CAD3 lay nearby. Re‐sequencing of the two phenylpropanoid genes via next‐generation amplicon sequencing revealed intragenic rearrangements and functionally relevant allelic variation in the three parents.     

Nitrogen release from different polymer-coated urea fertilizers in soil is affected by soil properties

The use of urea as nitrogen (N) fertilizer in agriculture needs to consider environmental, economic and resource conservation aspects because of low N-use efficiency (NUE). Polymer-coated urea (PCU) offers an effective way to improve the NUE of urea and to reduce its environmental trade-offs. However, we lack information on the impact of climate and soil properties on N release from PCU. Therefore, this study was performed to quantify the effects of soil texture, moisture and temperature on the release kinetics of N from PCU. We designed a test system for soil incubation experiments and investigated three fertilizers with different release patterns, five topsoils, three moisture levels and two temperatures over 48 days. We analysed the concentrations of inorganic N (${\mathrm{NH}}_4^{+}-\mathrm{N}$ and ${\mathrm{NO}}_3^{-}-\mathrm{N}$) in the soil and estimated N release rates using the unified Richards model. Soil texture did not change the N release patterns, but release rates varied significantly among the investigated soils. Changes in soil moisture for a given soil had no effect on N release from PCU and urea when fertilizers were incorporated into the soil at conditions supportive of crop growth. Lowering soil temperatures, however, decreased N release rates from PCU by 16%–49% but only in silt loam and not in sandy loam. We conclude that PCU improves the N residence time in soil, but predictions on N release from PCU must be adapted to the prevailing environmental conditions and cannot be generalized across differently textured soils.