Improvement of leaf wilting scoring system in cowpea (Vigna unguiculata (L) Walp.): From qualitative scale to quantitative index
Improvement of leaf wilting scoring system in cowpea (Vigna unguiculata (L) Walp.): From qualitative scale to quantitative index
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豇豆（Vigna unguiculata (L) Walp.）叶片萎蔫评分系统的改进：从定性尺度到定量指标
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发表时间：
2013
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通讯作者：
Mackson. Banda
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作者：
L. Pungulani;J. Millner;W. Williams;Mackson. Banda
叶片萎蔫是抗旱性评价的基本性状。然而，它的应用是有限的评分程序，这是与视觉评估和分类的基因型的基础上的定性尺度。这些局限性对没有经验的研究人员提出了重大挑战。本研究旨在完善豇豆品质评价体系，使其由定性指标向定量指标转变。在温室中对36份豇豆种质进行了评价。从发芽后第3周开始胁迫4周，在此期间对叶片总数、萎蔫叶片数、国际植物遗传资源委员会（IBPGR）等级、Mai-Kodomi（MAIK）等级和相对含水量（RWC）进行评分。在重新给植物浇水两周后，对茎的绿色度和再生进行评分。叶片萎蔫指数（LWI）计算为萎蔫叶片数与每株植物的总叶片数之间的比率。不同品种间的叶重、萎蔫度、相对含水量、再生长和茎绿度差异极显著（P<0.0001）。LWI与耐旱性状间也存在较强的相关性。LWI与干旱相关性状的相关性较强，表明LWI可用于豇豆萎蔫的评分。在4周的水分胁迫后，小于0.6的指数似乎是理想的，以鉴定耐旱基因型。通过计算个别萎蔫叶片的数量，可以减少与其他萎蔫尺度相关的挑战：从而使其成为测量豇豆和类似作物萎蔫水平的更简单，更可靠的方法。
Leaf wilting is a fundamental trait used in drought tolerance evaluation. However, its application is limited by a scoring procedure, which is associated with visual assessment and classification of genotypes based on qualitative scales. These limitations present significant challenges to non-experienced researchers. This current research was conducted, in order to improve the scoring system from qualitative scale to quantitative index in cowpeas. Thirty-six cowpea accessions were evaluated in a glasshouse. Plants were stressed for four weeks from the third week after germination, during which the total number of leaves, number of wilting leaves, International Board on Plant Genetic Resources (IBPGR) scale, Mai-Kodomi (MAIK) scale and relative water content (RWC) were scored. Stem greenness and regrowth were scored after re-watering the plants for two weeks. Leaf wilting index (LWI) was calculated as the ratio between the number of wilting leaves and the total number of leaves per plant. Highly significant variation (P<0.0001) was observed among accessions for LWI; wilting scales; relative water content; re-growth; and stem greenness. Strong correlations between LWI and drought tolerance traits were also observed. The strong correlations of LWI and drought related traits indicate that LWI could be used in scoring for wilting in cowpeas. An index of less than 0.6 appears to be ideal, in order to identify the drought tolerant genotypes, after four weeks of moisture stress. By counting the number of individual wilting leaves, the challenges associated with other wilting scales could be reduced: thus making it an easier and more reliable method for measuring wilting levels in cowpeas and similar crops.