Elevated temperatures associated with climate change result in crops being exposed to frequent spells of heat stress. Heat stress results in reduced yield in field pea (Pisum sativum L.); it is therefore important to identify cultivars with improved pod and seed retention under heat to mitigate this loss. Objectives were to investigate the effect of heat stress on phenology, yield and pod‐based yield components. Sixteen pea cultivars were evaluated at normal and late (hot) seeding dates in the field in Arizona 2012 and in growth chambers with two temperature regimes (24/18°C and 35/18°C day/night temperature for 7 days) during reproductive development. We measured variation in the pattern of pod retention at four‐node positions on plants, seed retention by ovule position (stylar, medial and basal) within pods and screened cultivars for pod retention, seed retention and yield. Heat stress reduced seed yield by accelerating the crop lifecycle and reducing pod number and seed size. Heat stress had the most damaging effect on younger reproductive growth (flowers and pods developed later), resulting in ovary abortion from developing flowers. Heat also accelerated seed abortion in all ovule positions within pods. Two high‐yielding cultivars under control temperature, “Naparnyk” and “CDC Meadow”, maintained high yield in heat, and “MFR043” had the lowest yield. Cultivars “40‐10” and “Naparnyk” retained the most ovules and seeds per pod, and “MFR043” aborted seeds when exposed to heat. In half of the cultivars, ovules at the basal peduncle end of pods were likely to abort while ovules at the medial and stylar end positions developed into seeds. For seven of the field cultivars, ovules at the medial pod position also produced mature seeds. Cultivars “40‐10”, “Naparnyk” and “CDC Meadow” had greater pod and ovule retention or maintained high yield under heat stress, and were identified as heat‐tolerant cultivars. Our results allow for a better understanding of pod‐based yield components in field pea under heat stress and developing heat‐tolerant cultivars.

中文翻译：

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热胁迫对豌豆荚果产量构成因素的影响（Pisum sativum L.）

与气候变化相关的温度升高导致农作物经常遭受热应激。热胁迫导致豌豆（Pisum sativum）产量下降L.）; 因此，重要的是鉴定在高温下具有改善的荚果和种子滞留性的品种，以减轻这种损失。目的是研究热胁迫对物候，产量和豆荚型产量成分的影响。在繁殖期间，在亚利桑那州2012年的田间和生长室中以正常温度和晚（热）播种日期对16个豌豆品种进行了评估，并在两种温度模式下（24/18°C和35/18°C白天/晚上温度，持续7天）发展。我们测量了植物四节点位置的荚果保留模式的变化，荚果中胚珠位置（种皮，内侧和基部）的种子保留，并筛选了荚果保留，种子保留和产量的品种。热应激通过加速作物生命周期并减少荚果数量和种子大小而降低了种子产量。热应激对较年轻的生殖生长（花朵和豆荚后来发育）具有最大的破坏作用，导致发育中的花朵导致卵巢流产。热还加速了豆荚内所有胚珠位置的种子流产。在控制温度下，两个高产品种“ Naparnyk”和“ CDC Meadow”在热量上保持高产量，而“ MFR043”的产量最低。品种“ 40-10”和“ Naparnyk”在每个豆荚中保留最多的胚珠和种子，而“ MFR043”在受热时则流产。在一半的品种中，豆荚的基部花序末端的胚珠可能会流产，而内侧和柱端的胚珠发育成种子。对于七个田间品种，中间荚位置的胚珠也产生成熟种子。品种“ 40-10”，在热胁迫下，“ Naparnyk”和“ CDC Meadow”具有较高的豆荚和胚珠滞留率或保持较高的产量，并被确定为耐热品种。我们的结果可以更好地了解热胁迫和发展耐热品种的豌豆中基于荚果的产量成分。