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• Morphometric and meristic variability in Butis koilomatodon in estuarine and coastal areas of the Mekong Delta

  Lam Thi Huyen Tran, Dinh Minh Quang

  Received: Jun 08, 2020 / Published: Dec 31, 2020

   Abstract PDF

  The study aimed to investigate morphometric and meristic variability in the mud sleeper Butis koilomatodon (Bleeker, 1849) in the Mekong Delta. This species is a commercial fish species with a small-size and is mainly distributed in some coastal areas from Tra Vinh to Ca Mau provinces. In the present research, the parameters of morphometry and measurement, including the head length, body depth, eye diameter, distance of the two eyes, and the interrelationships among the morphometric variables, were determined. The results revealed that the total length and weight of the fish changed by sex, season, habitat, and the interaction between the seasons and habitats. Likewise, the meristic criteria were different between males and females, and the dry and wet seasons, but not by their interactions. The growth rate of males was faster than females. The outcomes also showed that the body size of this species was larger in the dry season and the largest fish were found in Duyen Hai and Tra Vinh provinces. The Findings would be useful not only for further effects of environmental factors on morphology but also for comparisons between  congeners Butis morphologically.

• Comprehensive Analysis of Morphological Variation among 24 Tomato (Solanum Lycopersicum) Genotypes Oriented to Ornamental Breeding in Vietnam

  Tran Thien Long, Nguyen Hong Minh, Nguyen Tuan Anh, Tran Thi Minh Hang, Nguyen Thi Hoa, Nguyen Tien Long, Nguyen Thi Minh

  Received: Dec 23, 2019 / Published: Sep 30, 2020

   Abstract PDF

  Tomato is one of the most important vegetables cultivated in Vietnam. Besides its regular consumption as a vegetable, a new demand for using tomato as a decorative plant on special occasions was identified in recent years. This study aimed to characterize new tomato accessions on their desirable morphological traits to select potential materials for further breeding programs of ornamental tomato varieties in Vietnam. Twenty-four heirloom tomato genotypes were evaluated on 19 morphological traits. Based on the describing system for tomato developed by the International Plant Genetic Resources Institute (IPGRI, 1996), significant variation was assessed in both qualitative and quantitative traits related to fruit morphology. The results of principle component analysis indicated that three main principle components explained over 60% of the total phenotypic variation. The five traits of fruit size, fruit shoulder shape, fruit cross-sectional shape, number of locules, and shape of the pistil scar were recommended as important traits for clustering tomato genotypes in this study. In addition, the 24 genotypes were classified at the coefficient of 0.39 into six different clusters. Finally, six interesting accessions, AU66, AU67, AU68, AU73, AU79, and AU83 (with strange fruit colors and shapes), were selected as potential materials for further breeding programs of ornamental tomato in Vietnam.

• Allelopathy of Barnyardgrass (Echinochloa crus-galli) Weed: an Allelopathic Interaction with Rice (Oryza sativa)

  Tran Dang Khanh, Khuat Huu Trung, La Hoang Anh, Tran Dang Xuan

  Received: Aug 30, 2018 / Accepted: Aug 30, 2018 / Published: Aug 30, 2018

   Abstract PDF

  Barnyardgrass (Echinochloa crus-galli) is one of the most pernicious and problematic weeds in worldwide agriculture. The objective of this review is to highlight the morphology and habitats of this weed, and to present comprehensive information of the allelochemical constituents and pharmacological effects as well as its allelopathic interaction with rice (Oryza sativa L.) based on 115 worldwide literary resources reported over the last 40 years. In laboratory bioassays and root exudates experiments, barnyardgrass showed remarkable inhibition on the growth of the indicator plants. In greenhouse and field experiments, depending on the proportion density of barnyardgrass interference, rice yield is significantly reduced. Major isolated chemical constituents [including 59 compounds, belonging to phenolics, terpenes, steroids, lactones, long-fatty acids, and their derivatives] were identified and isolated from the different parts of this weed including root exudates and infested-soil, which are involved in allelopathic action. Among these, p-hydroxymandelic acids, diethyl phthalate, and two lactones [7,8-dihydro-5,6-dehydrokavain (DDK) and 7,8-dihydrokavain (DHK)], along with a gene cluster for the biosynthesis of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), may be responsible for the inhibitory effects of barnyardgrass in paddy fields. In attempts to elucidate the modes of action of these allelochemicals and allelopathic interactions between rice and barnyardgrass, it has been shown that the allelopathic actions of barnyardgrass and rice have similar responses in that they sense allelochemicals in the exudation of roots for enhancing allelopathic activity. However, the questions of which compounds play a main role in barnyardgrass allelopathy, and the actual modes of allelopathic interactions with rice remain unclear. This review may provide new insights into barnyardgrass’ adaptation and invasiveness as well as how the attributable interactions of all its present allelochemicals inhibit the growth of rice and the adjacent plants by allelochemical pathways.