Diversity Analysis and Molecular Taxonomy of Brassica Vegetable Crops

2000 ◽  
Vol 90 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Shu-Sheng Liu ◽  
Xin-Geng Wang ◽  
Shi-Jian Guo ◽  
Jun-Hua He ◽  
Zu-Hua Shi

AbstractAn investigation of insect parasitoids of the diamondback moth, Plutella xylostella(Linnaeus), in brassica vegetable crops in the suburbs of Hangzhou was conducted during five periods from 1989 to 1997. Eight species of primary parasitoids were recorded: Trichogramma chilonis Ishii, Cotesia plutellae Kurdjumov, Microplitis sp., Oomyzus sokolowskii Kurdjumov, Diadromus collaris(Gravenhorst), Itoplectis naranyae (Ashmead), Exochus sp. and Brachymeria excarinata Gahan. Seven species of hyperparasitoids were also collected. Rates of parasitism of eggs of P. xylostella were usually very low. However, rates of parasitism of larvae and pupae were substantial and showed two peaks each year, around June–July and September–November respectively. Rates of parasitism during peaks were usually 10–60% and reached over 80% on a few occasions. Cotesia plutellae, O. sokolowskii and D. collaris were the major larval, larval-pupal and pupal parasitoids respectively. In the field, C. plutellae was active throughout the year. Oomyzus sokolowskii was active from May to October, entered a quiescent pupal stage in October–November to overwinter and did not emerge until next April–May. Diadromus collariswas recorded from April to July and October. Rates of parasitism of P. xylostellain radish and mustard fields were usually higher than those in cabbage and Chinese cabbage fields in the same locality. Negative correlations of parasitism rates between C. plutellae and O. sokolowskii indicate a competitive relationship for host larvae between these two larval parasitoids.


1970 ◽  
Vol 12 (4) ◽  
pp. 677-684 ◽  
Author(s):  
D. R. Sampson

Thirty-two progenies showed a mean of 4.3 ± 0.3% recombination between ms-1, a gene for male sterility and c-1, a seedling marker gene. The closeness of this linkage makes it useful for producing F1 hybrid seed of Brassica vegetable crops. Differential viability, acting prior to seed germination and associated with the c-1 locus, resulted in either a deficiency or a surplus of ms-1 ms-1 plants depending on the linkage phase. The mean viability of plants with the C-1 phenotype was 1.26 ± 0.03 times that of c-1 c-1 plants. The genetic stocks studied bred true for a quadrivalent at meiosis I. This presumed duplication was traced through seven generations but was not responsible for the ms-1 c-1 linkage.


Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1721-1726 ◽  
Author(s):  
Charles S. Krasnow ◽  
Mary K. Hausbeck

The soilborne oomycete Phytophthora capsici causes root, crown, and fruit rot of many vegetable crops in the Cucurbitaceae and Solanaceae families. P. capsici is a persistent problem in vegetable fields due to long-lived oospores that survive in soil and resist weathering and degradation. Vegetable crops in the Brassicaceae family have been considered nonhosts of P. capsici and are planted as rotational crops in infested fields. Brassica spp. are also grown as biofumigation cover crops to reduce inoculum levels of P. capsici and other soilborne pathogens, and this use has increased concurrent with restrictions on soil fumigation. Oriental mustard (Brassica juncea), oilseed rape (B. napus), and oilseed radish (Raphanus sativus var. oleiferus) contain high levels of glucosinolates and are widely recommended for biofumigation and as cover crops. The objective of this study was to evaluate vegetables and biofumigation cover crops in the Brassicaceae family for susceptibility to P. capsici. Brassica spp. used as vegetable crops and for biofumigation were grown in P. capsici-infested potting soil in the greenhouse and disease incidence and severity were recorded. In greenhouse trials, infection by the pathogen reduced the fresh weight of all Brassica spp. tested and resulted in plant death of 44% of plants of B. juncea ‘Pacific Gold’. P. capsici isolates exhibited differences in virulence (P < 0.0001), and were reisolated from the roots of all Brassica spp. included in the study. The biofumigation cover crop Pacific Gold mustard may not reduce populations of P. capsici in soil and, instead, may sustain or increase pathogen levels. Further research is necessary to test this possibility under field conditions.


Author(s):  
Sarah C. Drury ◽  
Bruce D. Gossen ◽  
Mary Ruth McDonald

Clubroot, caused by the obligate pathogen <i>Plasmodiophora brassicae</i> Woronin, has been present on brassica vegetables in Ontario for decades, but was only recently identified on canola (<i>Brassica napus</i> L.). Once <i>P. brassicae</i> is present in a field, eradication is difficult, but resistant cultivars can provide effective management. Pathotype 6 has been the predominant pathotype on vegetable crops for decades, but pathotype 2 is predominant in canola fields in Ontario. Field trials were used to assess the reaction of selected canola and vegetable Brassica cultivars to pathotype 2, and controlled environment studies were conducted to evaluate the reaction of canola the same cultivars to pathotypes 2 and 6. Four canola cultivars with putative clubroot resistance were compared to two cultivars that were expected to be susceptible and three susceptible control cultivars. Several brassica vegetables were assessed: cabbage, cauliflower, broccoli, napa cabbage, rutabaga, and Shanghai pak choi (a susceptible control). The canola cultivars marketed as resistant were highly resistant in both the field and growth room trials. The canola cultivars not marketed as resistant were susceptible to pathotype 2, as expected. All of the canola cultivars were resistant to pathotype 6. The vegetable cultivars marketed as resistant or tolerant were resistant to pathotype 6 and most were resistant to pathotype 2. A putative resistant cultivar of cabbage and one of broccoli were resistant to pathotype 6 but susceptible to pathotype 2. Clubroot consistently reduced fresh shoot weight in susceptible cultivars of canola and brassica vegetables relative to resistant cultivars.


2000 ◽  
pp. 123-127
Author(s):  
T.S. Raijiciv ◽  
M. Ivancevic ◽  
D. Stevanovic ◽  
D. Vinterhalter

2013 ◽  
Vol 35 (3) ◽  
pp. 371-383 ◽  
Author(s):  
Kalpana Sharma ◽  
Bruce D. Gossen ◽  
Ronald J. Howard ◽  
Thomas Gludovacz ◽  
Mary Ruth McDonald

2004 ◽  
Vol 94 (2) ◽  
pp. 169-177 ◽  
Author(s):  
A.R. Mahmood ◽  
S.S. Liu ◽  
Z.H. Shi ◽  
X.H. Song ◽  
M.P. Zalucki

AbstractThe chalcid, Oomyzus sokolowskii Kurdjumov has been recorded in many parts of the world as a major larval–pupal, gregarious endoparasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. This study investigated intraspecific variation between two populations of O. sokiolowskii, one from Cape Verde Islands, West Africa and the other from Hangzhou, China. In all crosses and backcrosses between the two geographical populations, the numbers of progeny and sex ratio of progeny were similar to those obtained within each of the populations, demonstrating complete reproductive compatibility between the two populations. The two populations showed similar responses to temperature with respect to development time and survival of immature stages. Observations on the interactions between the two O. sokolowskii populations and Cotesia plutellae (Kurdjumov), another major parasitoid of P. xylostella, showed that neither population could achieve successful parasitism of P. xylostella larvae already parasitized by C. plutellae. However, both O. sokolowskii populations could achieve hyperparasitism by ovipositing into a mid-late stage larva of C. plutellae developing inside the primary host. Contrary to earlier reports, no evidence of intraspecific variations in ability to hyperparasitize between these two populations of O. sokolowskii was found.


2021 ◽  
pp. 104832
Author(s):  
Valkíria Fabiana da Silva ◽  
Alexandre dos Santos ◽  
Luís Cláudio Paterno Silveira ◽  
Vitor Barrile Tomazella ◽  
Raul Magalhães Ferraz

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