Heat stress can seriously reduce the tuber yield of potato (Solanum tuberosum). Early maturing cultivars are usually less affected by heat than late cultivars, which is explained by the avoidance of long exposure to summer temperatures due to the short growing time of early maturing cultivars. To determine whether there are other mechanisms involved in heat tolerance of early cultivars, we conducted correlation analysis between field earliness and growth performance of 50 potato cultivars under both heat-stressed (HS, day/night 35 °C/28 °C) and control conditions (CK, day/night 22 °C/18 °C). We classified the 50 cultivars into 8 scales of earliness and grouped them into early, intermediate and late groups based on the information on field plant maturity in Canada. We found that cultivars known to be early in the field grew similar to late cultivars under heat stress in the greenhouse in terms of traits evaluated, such as chlorophyll content and plant height. Compared with late cultivars, the early cultivars did not show any sign of early maturity under heat stress conditions. The HS/CK ratios of chlorophyll content, plant height, and largest tuber weight (tuber size) were all significantly greater in early cultivars than in late cultivars. Tuber size and field earliness were negatively correlated in CK but positively correlated under heat stress. Clearly, in addition to avoidance, other mechanisms (such as pleiotropic effects of earliness genes) were involved in the better performance of early cultivars under heat stress. These results indicated that the cultivars reprogramed their plant maturity and development under heat stress.

中文翻译：

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早熟对五十个马铃薯品种耐热胁迫的影响

热应激会严重降低马铃薯的块茎产量（马铃薯））。与早熟品种相比，早熟品种受热量的影响通常较小，这可以解释为避免由于早熟品种的生长时间短而长时间暴露于夏季温度。为了确定是否有其他机制影响早熟品种的耐热性，我们在热胁迫（HS，昼/夜35°C / 28°C）和对照下对50个马铃薯品种的田间早期性和生长性能之间进行了相关性分析。条件（CK，日/夜22°C / 18°C）。根据加拿大田间植物成熟度的信息，我们将50个品种分为8个早期等级，并分为早期，中级和晚期组。我们发现，就评估的性状而言，已知在田间早期的品种在温室热胁迫下的生长与晚期品种相似，例如叶绿素含量和植物高度。与晚期品种相比，在热胁迫条件下，早期品种没有任何早熟迹象。在早期品种中，叶绿素含量，株高和最大块茎重量（块茎大小）的HS / CK比均显着大于晚期品种。块茎大小和田间早熟度在CK中呈负相关，但在热胁迫下呈正相关。显然，除避免外，其他机制（例如早期基因的多效性）也参与了热胁迫下早期品种的更好表现。这些结果表明，在热胁迫下，栽培品种对植物的成熟和发育进行了重新编程。早期品种在热胁迫条件下没有显示出任何早期成熟的迹象。在早期品种中，叶绿素含量，株高和最大块茎重量（块茎大小）的HS / CK比均显着大于晚期品种。块茎大小和田间早熟度在CK中呈负相关，但在热胁迫下呈正相关。显然，除避免外，其他机制（例如早期基因的多效性）也参与了热胁迫下早期品种的更好表现。这些结果表明，在热胁迫下，栽培品种对植物的成熟和发育进行了重新编程。早期品种在热胁迫条件下没有显示出任何早期成熟的迹象。在早期品种中，叶绿素含量，株高和最大块茎重量（块茎大小）的HS / CK比均显着大于晚期品种。块茎大小和田间早熟度在CK中呈负相关，但在热胁迫下呈正相关。显然，除避免外，其他机制（例如早期基因的多效性）也参与了热胁迫下早期品种的更好表现。这些结果表明，在热胁迫下，栽培品种对植物的成熟和发育进行了重新编程。块茎大小和田间早熟度在CK中呈负相关，但在热胁迫下呈正相关。显然，除避免外，其他机制（例如早期基因的多效性）也参与了热胁迫下早期品种的更好表现。这些结果表明，在热胁迫下，栽培品种对植物的成熟和发育进行了重新编程。块茎大小和田间早熟度在CK中呈负相关，但在热胁迫下呈正相关。显然，除了避免外，其他机制（例如早期基因的多效性）也参与了热胁迫下早期品种的更好表现。这些结果表明，在热胁迫下，栽培品种对植物的成熟和发育进行了重新编程。