Modern Cannabis cultivars are morphologically distinguished by their leaflet shapes (wide for “Indica” and narrow for “Sativa”) by users and breeders. However, there are no scientific bases or references for determining the shape of these leaflets. In addition, these two categories contained mostly THC dominant (high THC) cultivars while excluded CBD dominant (high CBD) and intermediate (intermediate level of both THC and CBD) cultivars. This study investigated the phenotypic variation in 21 Cannabis cultivars covering three chemical phenotypes, referred to as chemotypes, grown in a commercial greenhouse. Thirty morphological traits were measured in the vegetative, flowering, and harvest stages on live plants and harvested inflorescences. The collected data were subjected to correlation analysis, hierarchical clustering, principal component analysis, and canonical correlation analysis with preassigned chemotypes. Canonical correlation analysis assigned individual plants to their chemotypes with 92.9% accuracy. Significant morphological differences were identified. Traits usable as phenotype markers for CBD dominant cultivars included light-green and narrow leaflets, a greater number of primary and secondary serrations, loose inflorescences, dense and resinous trichomes, and Botrytis cinerea resistance. Traits for intermediate cultivars included deep-green and medium-wide leaflets, more primary and secondary serrations, medium compact inflorescences, trichomes that are less dense and less resinous, and Botrytis cinerea resistance. Traits for THC dominant cultivars included deep-green and wide leaflets, large and compact inflorescences, dense and resinous trichomes, and Botrytis cinerea susceptibility. The results of this study provide a comprehensive profile of morphological traits of modern Cannabis cultivars and provides the first such profile for CBD dominant and intermediate cultivars. Additionally, this study included the traits of inflorescences, which have not been compared between three chemotypes in the literature. Phenotype markers identified in this study can facilitate preliminary cultivar identification and selection on live plants before or as a supplement to chemical and genetic analysis.
Dan Jin, Philippe Henry, Jacqueline Shan, and Jie Chen
Joyce W. Ngure, Chunyan Cheng, Shuqiong Yang, Qunfeng Lou, Ji Li, Chuntao Qian, Jie Chen, and Jinfeng Chen
Cucumber (Cucumis sativus) seed oil has the potential for use as an edible oil and as a pharmaceutical, cosmetic, insecticidal, and industrial product. In this study, we investigated, for the first time, the effect of cultivar and season on seed number, oil content, and fatty acid profiles as well as their proportions in different cucumber cultivars. We examined the effects of spring and autumn seasons on seed oil content and fatty acid composition in 46 cucumber cultivars and one wild species of cucumber (C. anguria) grown in greenhouse experiments in 2013 and 2014. Seed oil was determined using the Soxhlet method and fatty acids using the gas chromatography-mass spectrometry method. Seed oil content in the cucumber seeds ranged from 41.07% in ‘Hazerd’ to 29.24% in ‘Lubao’ while C. anguria had 23.3%. Fatty acids detected were linoleic (C18:2), palmitic (C16:0), oleic (C18:1), stearic (C18:0), linolenic (C18:3), behenic (C22:0), arachidic C20:0), lignoceric (C24:0), eicosenoic (C20:1), palmitoleic (C16:1), and myristic (C14:0), among other unidentified fatty acids. The results showed significant effects of cultivar genotype, growing season, and interactions on the variables examined. The content of seed oil and fatty acids differed significantly among the cultivar genotypes. Spring-grown cucumbers had higher quantities of oil than the autumn-grown cucumbers. The content of fatty acids (mainly palmitic, palmitoleic, stearic, oleic, eicosenoic, and lignoceric) also was higher in spring. In autumn there were more seeds, and higher linoleic, linolenic, and other unspecified fatty acids. The higher the oleic acid content the lower was the linoleic acid indicating a strong negative relationship in these two fatty acids. The higher the seed oil content the higher was linoleic and oleic indicating a positive relationship between the seed oil and the two fatty acids. Results of this study provide important information applicable in improving management and production of cucumber seed oil especially considering its versatility in uses. Furthermore, the wide range of fatty acids found in the studied cucumber cultivars could be used in the production of novel industrial oils through genetic engineering.
Lingyun Yuan, Yujie Yuan, Shan Liu, Jie Wang, Shidong Zhu, Guohu Chen, Jinfeng Hou, and Chenggang Wang
High temperature (HT) is a major environmental stress limiting oversummer production of nonheading Chinese cabbage (NHCC, Brassica campestris ssp. chinensis Makino). In the present study, the effects of HT on photosynthetic capacity, including light reaction and carbon assimilation, were completely investigated in two NHCC, ‘xd’ (heat-tolerant), and ‘sym’ (heat-susceptible). The two genotypes showed significant differences in plant morphology, photosynthetic capacity, and photosynthate metabolism (carboassimilation). HT caused a decrease in photosynthesis, chlorophyll contents, and photochemical activity in NHCC. However, these main photosynthetic-related parameters, including net photosynthetic rate (PN), maximal photochemical efficiency of PSII (Fv/Fm), and total chlorophyll content in ‘xd’, were significantly higher than those of ‘sym’ plants. The antioxidant contents and antioxidative enzyme activities of ascorbic acid-reduced glutathione cycle in the chloroplast of ‘xd’ were significantly higher than those of ‘sym’. Microscopic analyses revealed that HT affected the structure of photosynthetic apparatus and membrane integrity to a different extent, whereas ‘xd’ could maintain a better integrated chloroplast shape and thylakoid. Inhibited light reaction also hampered carbon assimilation, resulting in a decline of carboxylation efficiency and imbalance of carbohydrate metabolism. However, larger declined extents in these data were presented in ‘sym’ (heat-susceptible) than ‘xd’ (heat-tolerant). The heat-tolerant genotype ‘xd’ had a better capacity for self-protection by improved light reaction and carbon assimilation responding to HT stress.