Weedy rice (Oryza sativa f. spontanea Rosh.) is an emerging weed of California rice (Oryza sativa L.) that has potential to cause large yield losses. Early detection of weedy rice in the field is ideal to effectively control and prevent the spread of this weed. However, it is difficult to differentiate weedy rice from cultivated rice during early growth stages due to the close genetic and phenotypic relatedness of cultivated rice and weedy rice. The objective of this study is to examine phenotypic variation in weedy rice biotypes from California and to identify traits that could be used to visually identify weedy rice infestations at early growth stages for effective management. Greenhouse experiments were conducted in 2017 and 2018 using five phenotypically distinct biotypes of weedy rice found in California, along with diverse cultivated, weedy, and wild rice types in a randomized complete block design. We measured variation for 13 phenotypic traits associated with weedy rice and conducted principal component analysis and factor analysis to identify important weedy traits. Most weedy rice individuals within a biotype clustered together by phenotypic similarity. Pericarp color, hull color, chlorophyll content, grain length, plant height, leaf pubescence, collar color, and leaf sheath color account for most of the observed variation. California weedy rice biotypes are phenotypically distinct from wild rice and from weedy rice from the southern United States in their combinations of seed phenotypes and vegetative characteristics. In comparison with the locally grown temperate japonica cultivars, California weedy rice tends to be taller, with lower chlorophyll content and a red pericarp. Weedy rice biotypes vary in seed shattering and seed dormancy. For weedy rice management, plant height and chlorophyll content are distinct traits that could be used to differentiate weedy rice from the majority of cultivated rice varieties in California during vegetative stages of rice growth.

中文翻译：

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在加利福尼亚发现的杂草稻 (Oryza sativa f. spontanea) 生物型的表型多样性及其管理意义

杂草饭（水稻F。自发性Rosh.) 是一种新兴的加利福尼亚水稻杂草 (水稻L.) 有可能导致大量产量损失。早期发现田间杂草稻是有效控制和防止杂草蔓延的理想选择。然而，由于栽培稻和杂草稻的遗传和表型密切相关，在生长早期很难区分杂草稻和栽培稻。本研究的目的是检查加利福尼亚杂草稻生物型的表型变异，并确定可用于在早期生长阶段直观地识别杂草稻侵扰以进行有效管理的性状。温室实验于 2017 年和 2018 年使用在加利福尼亚发现的五种表型不同的杂草稻生物型，以及采用随机完整区组设计的各种栽培稻、杂草和野生稻类型进行。我们测量了与杂草稻相关的 13 个表型性状的变异，并进行了主成分分析和因子分析，以确定重要的杂草性状。生物型中的大多数杂草稻个体通过表型相似性聚集在一起。果皮颜色、外壳颜色、叶绿素含量、粒长、株高、叶短柔毛、衣领颜色和叶鞘颜色占观察到的大部分变化。加利福尼亚杂草稻生物型在种子表型和营养特征的组合上与野生稻和美国南部杂草稻的表型不同。与当地种植的温带相比 生物型中的大多数杂草稻个体通过表型相似性聚集在一起。果皮颜色、外壳颜色、叶绿素含量、粒长、株高、叶短柔毛、衣领颜色和叶鞘颜色占观察到的大部分变化。加利福尼亚杂草稻生物型在种子表型和营养特征的组合上与野生稻和美国南部杂草稻的表型不同。与当地种植的温带相比 生物型中的大多数杂草稻个体通过表型相似性聚集在一起。果皮颜色、外壳颜色、叶绿素含量、粒长、株高、叶短柔毛、衣领颜色和叶鞘颜色占观察到的大部分变化。加利福尼亚杂草稻生物型在种子表型和营养特征的组合上与野生稻和美国南部杂草稻的表型不同。与当地种植的温带相比 加利福尼亚杂草稻生物型在种子表型和营养特征的组合上与野生稻和美国南部杂草稻的表型不同。与当地种植的温带相比 加利福尼亚杂草稻生物型在种子表型和营养特征的组合上与野生稻和美国南部杂草稻的表型不同。与当地种植的温带相比粳稻品种，加利福尼亚杂草稻往往更高，叶绿素含量更低，果皮红色。杂草稻生物型在种子破碎和种子休眠方面有所不同。对于杂草稻管理，株高和叶绿素含量是不同的特征，可用于在水稻生长的营养阶段将杂草稻与加利福尼亚的大多数栽培稻品种区分开来。