Martin Sara L, Lujan-Toro Beatriz E, Sauder Connie A, James Tracey, Ohadi Sara, Hall Linda M
Ottawa Research and Development Centre Agriculture and Agri-food Canada Ottawa Ontario.
Agricultural Food and Nutritional Science University of Alberta Edmonton Alberta.
Evol Appl. 2018 Dec 1;12(3):443-455. doi: 10.1111/eva.12724. eCollection 2019 Mar.
Hybridization between crops and their wild relatives has the potential to introduce novel variation into wild populations. Camelina () is a promising oilseed and cultivars with modified seed characteristics and herbicide resistance are in development, prompting a need to evaluate the potential for novel trait introgression into weedy relatives. Little-podded false flax (littlepod) is a naturalized weed in Canada and the USA. Here we evaluated the hybridization rate between the three cytotypes of littlepod (♀) and camelina (♂), assessed characteristics of hybrids, and evaluated the fitness of hexaploid littlepod and camelina hybrids in the glasshouse and field. In total we conducted, 1,005 manual crosses with diploid littlepod, 1, 172 crosses with tetraploid littlepod, and 896 crosses with hexaploid littlepod. Hybrids were not produced by the diploids, but were produced by the tetraploids and hexaploids at rates of one hybrid for 2,000 ovules pollinated and 24 hybrids for 25 ovules pollinated, respectively. Hybrids between tetraploid littlepod and camelina showed low pollen fertility and produced a small number of seeds. In the glasshouse, hybrids between hexaploid littlepod and camelina also showed significantly lower pollen fertility and seed production than parental lines, but their seeds showed high viability. A similar pattern was observed in field trials, with hybrids showing earlier flowering, reduced biomass, seed production and seed weight. However, seed produced by the hybrids showed greater viability than that produced by hexaploid littlepod and is potentially the result of a shortened lifecycle. The introgression of lifecycle traits into littlepod populations may facilitate range expansion and contribute to crop gene persistence. Consequently, future work should evaluate the hybridization rate in the field, the fitness of advanced generation backcrosses, and the role of time to maturity in limiting hexaploid littlepod's distribution.
作物与其野生近缘种之间的杂交有可能将新的变异引入野生种群。亚麻荠（Camelina）是一种很有前景的油料作物，目前正在培育具有改良种子特性和抗除草剂能力的品种，这就需要评估新性状渗入其杂草近缘种的可能性。小荚假亚麻（littlepod）是加拿大和美国的一种归化杂草。在此，我们评估了小荚假亚麻三种细胞型（♀）与亚麻荠（♂）之间的杂交率，评估了杂种的特性，并在温室和田间评估了六倍体小荚假亚麻与亚麻荠杂种的适合度。我们总共进行了1005次与二倍体小荚假亚麻的人工杂交、1172次与四倍体小荚假亚麻的杂交以及896次与六倍体小荚假亚麻的杂交。二倍体未产生杂种，但四倍体和六倍体产生了杂种，授粉2000个胚珠分别产生1个杂种，授粉25个胚珠分别产生24个杂种。四倍体小荚假亚麻与亚麻荠的杂种花粉育性较低，种子产量较少。在温室中，六倍体小荚假亚麻与亚麻荠的杂种花粉育性和种子产量也显著低于亲本系，但其种子活力较高。在田间试验中也观察到了类似的模式，杂种开花较早，生物量、种子产量和种子重量降低。然而，杂种产生的种子比六倍体小荚假亚麻产生的种子活力更高，这可能是生命周期缩短的结果。生命周期性状渗入小荚假亚麻种群可能有助于其分布范围的扩大，并有助于作物基因的持久存在。因此，未来的工作应评估田间的杂交率、高世代回交的适合度以及成熟时间在限制六倍体小荚假亚麻分布方面的作用。
