玉米的主要部分是在热带地区的雨养条件下生产的,由于季节性降雨的不可预测和不规则分布,产量相对较差,以及由于气候变化导致的雨季前降雨量减少,因此,最需要确定可持续生产选择。因此,本研究是在温室(GH)中进行的,以确定玉米的耐水胁迫性状,并在泰国的热带环境中在田间进行,以了解使用乙烯利在当地流行品种中确定性状的刺激可能性。根据公差级别,在不同的水分条件下测试了三种玉米基因型(Suwan2301>Suwan4452>S7328),短期,和长期水分胁迫在GH。在现场一级,对当地流行的玉米品种Suwan5819进行了六个乙烯利水平的检查(剂量以ga.i.ha-1的乙烯利,即,V6阶段的T1,281;V10阶段的V6,281的T2,281;V10阶段的T3,281;V6阶段的T4,562;V6阶段的T5,562;V10阶段的V6562;V10阶段的T6,562)在雨养条件下不施加乙烯利(T0)。玉米在播种后的26-39天(DAP)和田间的43-63DAP中缺乏充足的降雨。从双plot分析中将产量指数(YI)确定为GH和热带地区田间玉米耐旱性检查的合适标准之一。GH中玉米的农业生理生化性状的YI值表明,相对含水量(RWC,1.23),阀杆基部直径(SBD,1.21),总可溶性糖(TSS,1.15),脯氨酸(Pr,1.13),地上植物生物量(APB,1.13),根重(RW,1.13),相对增长率(RGR,1.15),比叶重(SLW,1.12),和净同化率(NAR,1.08)是最可取的。努力在田间水分胁迫下刺激这些性状。在较高的RWC(90.38%)的支持下,作为T1的乙烯利应用有助于获得更高的籽粒产量(KY)(5.26tha-1),脯氨酸(24.79µmolg-1FW),TSS(1629mgg-1FW),SBD(24.49mm),APB(271.34gplant-1),SLW(51.71gm-2),RGR(25.26毫克植物-1天-1),与其他相比,NAR(0.91mgcm-2day-1),尤其是没有应用乙烯利。此外,属性SLW,SBD,Pr,热利用效率(HUE),100-kernelweight,TSS,电解液泄漏,倒伏率与KY表现出显著的直接效应和显著的相关性。除了更高的KY,乙烯利作为T1战术的应用导致了更高的能源效率值(1.66),HUE(2.99千克公顷-1°C天-1),毛利率(682.02美元ha-1),MBCR(3.32),和碳吸收(6.19tCha-1),表明这种做法可能是雨养条件下玉米可持续生产的良好选择。
A major portion of maize is produced under rainfed conditions in the tropics with relatively poor yield because of the unpredictable and irregular distribution of seasonal rainfall, as well as a decline in pre-rainy season rainfall due to climate change, so identification of sustainable production options is utmost needed. Thus, the present studies were conducted in a greenhouse (GH) to ascertain the water stress-tolerant traits of maize and at the field level in the tropical environment of Thailand to see the stimulating possibility of the ascertained traits in a locally popular cultivar using ethephon. Depending on tolerance level, three maize genotypes (Suwan 2301 > Suwan 4452 > S 7328) were tested under different water conditions-well-watered, short-term, and long-term water stress-in the GH. At the field level, the locally popular maize cultivar Suwan 5819 was examined with six
ethephon levels (doses in g a.i. ha-1 of
ethephon, i.e., T1, 281 at V6 stage; T2, 281 at V6 + 281 at V10 stage; T3, 281 at V10 stage; T4, 562 at V6 stage; T5, 562 at V6 + 562 at V10 stage; T6, 562 at V10 stage) against no
ethephon application (T0) under rainfed conditions. Maize suffered from the scarcity of sufficient rainfall during 26-39 days after planting (DAP) and 43-63 DAP in the field. The yield index (YI) was identified from biplot analysis as one of the suitable standards for drought tolerance checks for maize at GH as well as at field level in the tropics. The YI value of observed agro-physio-biochemical traits of maize in GH showed that relative water content (RWC, 1.23), stem base diameter (SBD, 1.21), total soluble sugar (TSS, 1.15), proline (Pr, 1.13), aboveground plant biomass (APB, 1.13), root weight (RW, 1.13), relative growth rate (RGR, 1.15), specific leaf weight (SLW, 1.12), and net assimilation rate (NAR, 1.08) were the most desirable. Efforts were made to stimulate these traits under water stress at the field level.
Ethephon application as T1 helped to gain higher kernel yield (KY) (5.26 t ha-1) with the support of higher RWC (90.38%), proline (24.79 µmol g-1 FW), TSS (1629 mg g-1 FW), SBD (24.49 mm), APB (271.34 g plant-1), SLW (51.71 g m-2), RGR (25.26 mg plant-1 day-1), and NAR (0.91 mg cm-2 day-1) compared to others, especially no ethephon application. Furthermore, the attributes SLW, SBD, Pr, heat utilization efficiency (HUE), 100-kernel weight, TSS, electrolyte leakage, and lodging percentage showed a substantial direct effect and significant correlation with KY. Aside from higher KY,
ethephon application as T1 tactics resulted in higher values of energy efficiency (1.66), HUE (2.99 kg ha-1 °C days-1), gross margin (682.02 USD ha-1), MBCR (3.32), and C absorption (6.19 t C ha-1), indicating that this practice may be a good option for maize sustainable production under rainfed conditions.