Large scale germplasm screening for Chilo partellus resistance in maize is solely based on visual scoring of damage by leaf injury rating (LIR), where the accuracy in judging a genotype comes by experience of the person, who logically integrate certain symptoms such as levels of growth retardation. Since the pest spends more than half of its larval period damaging the stalk, a quantitative phenotyping method that gives weightage to stalk resistance is required. To explore the traits governing stalk resistance, stalk infestation behaviour of C. partellus was studied first. It was found that first instar C. partellus larva is exclusive whorl feeder, second instar is the transition stage which disperse to infest stalk, and third instar onwards are exclusive stalk borers. To access the stalk, larva tends to penetrate the second above ground internode (seventh internode of maize plant) of V6–10 stage maize. Thus, penetration resistance (PR) of seventh internode was hypothesized to be the characteristic resistance trait. Twenty elite maize breeding lines were evaluated for PR of rind (RPR) and pith (PPR) of seventh internode in V6–7, V8–9 and V10–11 stage plants by TA + Di Texture Analyzer. Significant negative correlation of LIR with RPR of all plant stages and with PPR of V6–7 stage plants suggests the ability of seventh internode to resist larval penetration would confer tolerance to C. partellus. The trait was also found a strong predictor of antibiosis, by affecting the biology and behaviour of C. partellus larva. Thus, PR of seventh internode is proposed to be the trait for phenotyping stalk resistance to C. partellus in maize, whose deployment could lead to selection of genotypes which are resistant to stalk lodging also.

中文翻译：

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V6-10 期玉米植株地上第二节间的渗透抗性赋予玉米中 Chilo partellus (Swinhoe) 茎螟幼虫抗性

大规模种质筛选玉米中的 Chilo partellus 抗性完全基于叶片损伤等级 (LIR) 的损伤视觉评分，其中判断基因型的准确性来自于人的经验，他们逻辑地整合了某些症状，例如生长水平迟缓。由于害虫花费超过一半的幼虫期来破坏茎，因此需要一种定量表型方法来衡量茎的抗性。为了探索控制茎秆抗性的性状，首先研究了C. partellus的茎秆侵染行为。发现一龄C. partellus幼虫为独生轮生食虫，二龄为分散侵染茎秆的过渡期，三龄及以后为独生茎螟。要访问茎，幼虫倾向于穿透 V6-10 期玉米的地上第二个节间（玉米植株的第七个节间）。因此，假设第七节间的穿透阻力（PR）是特征阻力特征。通过 TA + Di Texture Analyzer 对 20 个优良玉米育种品系的 V6-7、V8-9 和 V10-11 阶段植物的第七节间的果皮 (RPR) 和髓 (PPR) 的 PR 进行了评估。LIR 与所有植物阶段的 RPR 以及与 V6-7 阶段植物的 PPR 的显着负相关表明第七节间抵抗幼虫渗透的能力将赋予对 C. partellus 的耐受性。通过影响 C. partellus 幼虫的生物学和行为，该特征还被发现是抗生素的强预测因子。因此，提出第七节间的 PR 是玉米茎对 C. partellus 抗性的表型性状，