J. B. Davis

Intergeneric hybridization between Sinapis alba and Brassica napus

Researchers have conclusively shown that Sinapis alba (commonly known as yellow mustard) has many agronomic traits which would be beneficial if transferred to rapeseed ( Brassica napus L.). S. alba is resistant or tolerant to all major insect pests of Brassica crops in the Pacific Northwest region of the United States of America. It is also tolerant of high temperatures and drought stress, is shatter resistant and capable of high seed yield without the need for insecticides and herbicides. However, S. alba is considerably lower in oil content and lacks the high oil quality and seed meal quality of rapeseed (i.e. canola). This paper describes a combination of ovary culture and embryo rescue techniques used to develop fertile hybrid plants from the intergeneric cross between S. alba and B. napus . The hybrids were intermediate between both parents for presence of trichomes, leaf shape and color, seed size, pod shape, and seed oil content; showing expression of traits from both parental species. Hybrid plant tissue and seed contained all types of glucosinolate that exists in either B. napus or S. alba, at the same or higher level to the parental species. These hybrid crosses offer the potential for combining the desirable oil and glucosinolate qualities of B. napus with insect and disease resistance characters of S. alba.

Effect of late season insect infestation on yield, yield components and oil quality of Brassica napus , B. rapa , B. juncea and Sinapis alba in the Pacific Northwest region of the United States

The effect of late season insect infestation on seed yield, yield components, oil content and oil quality of two canola species ( Brassica napus L. and B. rapa L.) and two mustard species ( B. juncea L. and Sinapis alba L.) was examined over 2 years. In each year, ten genotypes from each species were evaluated with late season insects controlled with either methyl parathion or endosulfan insecticides, and without insecticides. Major late season insect damage in 1992 was caused by cabbage seedpod weevil ( Ceutorhynchus assimilis Paykull), while diamondback moth ( Plutella xylostella L.) and aphids (primarily cabbage aphids, Brevicoryne brassicae L.) were major insect pests in 1993. Insecticide application was very effective in controlling diamondback moth larvae and adult cabbage seedpod weevils, but only partially effective in controlling aphids. Higher numbers of diamondback moth larvae were observed on mustard species compared to canola species. S. alba was completely resistant to cabbage seedpod weevil and there was no damage due to this pest observed. Aphid colonization was observed on plants from all species, but infestation on S. alba and B. rapa occurred too late to have a major effect on seed yield. Seed oil content of canola species was significantly reduced by insect damage although oil quality (indicated by fatty acid profile) was not affected by insect attack. Uncontrolled insect infestation reduced seed yield of canola species by 37 and 32% in B. napus and B. rapa , respectively. Least yield reduction occurred in S. alba , where average yield reduction from plants in untreated control plots was S. alba , therefore, has good potential as an alternative crop suitable for northern Idaho because it can be grown with reduced late season insecticide application.

Effect of replacing solvent-extracted canola meal with high-oil traditional canola, high-oleic acid canola, or high-erucic acid rapeseed meals on rumen fermentation, digestibility, milk production, and milk fatty acid composition in lactating dairy cows

The objective of this experiment was to investigate the effects of replacing conventional, solvent-extracted canola meal (control; CTRL) with high oil content; conventional, mechanically extracted canola meal (CMEC); high-oleic, low polyunsaturated fatty acid (FA) canola meal (HOLL); and high-erucic acid, low-glucosinolate rapeseed meal (RPS) on rumen function, digestibility, milk production, and milk FA composition in lactating dairy cows. The experimental design was a replicated 4×4 Latin square with 8 lactating dairy cows. Four of the cows were ruminally cannulated. All oilseed meals were included at approximately 12 to 13% of dietary dry matter (DM). Crude protein and fat concentrations (% of DM) of the meals were 43 and 3.1%, 32.8 and 16.1%, 45.2 and 13.7%, and 34.3 and 17.9% for CTRL, CMEC, HOLL, and RPS, respectively. All diets were formulated to supply net energy of lactation in excess of requirements. The CMEC and RPS diets were predicted to be about 1% deficient in metabolizable protein. Relative to the CTRL, inclusion of high-oil seed meals in the diet lowered ruminal acetate concentration and the molar acetate:propionate ratio and decreased DM intake. Milk yield generally followed DM intake and was lower for CMEC and RPS than the CTRL. Treatments had no effect on milk composition, other than an increase in milk urea nitrogen concentration for HOLL. Fat-corrected milk (3.5%) feed efficiency was increased by HOLL and RPS compared with CTRL. Urinary urea nitrogen losses were increased by HOLL, which, as a consequence, increased the ammonia-emitting potential of manure. The ratio of milk N-to-N intake was greater for CMEC and RPS. Replacing solvent-extracted canola meal with the high-oil meal decreased milk fat 12:0, 14:0, 16:0, and total saturated FA content and enhanced cis-9 18:1 and total monounsaturated FA concentrations. Relative to the CTRL, canola increased total trans FA in milk, whereas inclusion of HOLL in the diet increased trans-11 18:1 and cis-9, trans-11 CLA content. The RPS increased milk fat cis-13 22:1 content from 0.07 to 2.33 g/100g of FA. In conclusion, HOLL or RPS, which are likely to come from small-scale biodiesel plants where oil is cold pressed without hexane extraction, fed at levels at or above 12 to 13% of dietary DM may decrease feed intake and milk production, but can be used to alter milk FA composition in lactating dairy cows.

Assessment of Sinapis alba, Brassica napus and S. alba × B. napus hybrids for resistance to cabbage seedpod weevil, Ceutorhynchus assimilis (Coleoptera: Curculionidae).

Canola (Brassica napus L.), yellow mustard (Sinapis alba L.) and intergeneric crosses of S. alba × B. napus were assessed for resistance (antixenosis) to the cabbage seedpod weevil (Ceutorhynchus assimilis Paykull). Pod trichomes did not appear to be a major factor in the resistance of S. alba to weevils. The number of feeding punctures and eggs per pod in S. alba was not significantly different in pods with trichomes than in those where the trichomes had been removed. Choice and no-choice laboratory tests examining feeding punctures and eggs laid per pod suggested that resistance in S. alba is not conferred in the intergeneric cross, S. alba × B. napus. Similar data on feeding and weevil oviposition were found in field test plots. However, despite many eggs being laid in S. alba × B. napus hybrid plants, fewer cabbage seedpod weevil larvae developed to exit the intergeneric hybrid pods. Glucosinolate analyses of leaves, pods and seeds showed that S. alba plants have a high concentration of p-hydroxybenzyl glucosinolate in all three plant parts, but B. napus has no p-hydroxybenzyl. Interestingly the intergeneric hybrid examined in this study had 62% and 60% of p-hydroxybenzyl concentration in the leaves and seeds, respectively, than was found in the S. alba parent. However, pod tissues contained very little (3 %) compared with the S. alba parent. It is possible, therefore, that the adult cabbage seedpod weevil feeds on the pods of the intergeneric hybrid and lays eggs in the pod, because of the low concentration ofp-hydroxybenzyl glucosinolate, but the larvae then fail to develop as they feed on the seeds containing high concentrations of p-hydroxybenzyl glucosinolate. It should be noted also that this hybrid produced pods that were more similar in physical shape to canola pods and that this may also be a factor determining cabbage seedpod weevil feeding and subsequent egg laying. In addition, both B. napus and the intergeneric hybrid produced 3-butenyl and 4-pentenyl glucosinolates in their pods, and degradation products (3-butenyl, and 4-pentenyl isothiocyanates) from these glucosinolate types, are known to be stimulatory kairomones that attract cabbage seedpod weevil. Further studies are being conducted to examine these factors in more detail.

Yield Reduction in Brassica napus, B. rapa, B. juncea, and Sinapis alba Caused by Flea Beetle (Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae)) Infestation in Northern Idaho

Abstract Phyllotreta cruciferae is an important insect pest of spring-planted Brassica crops, especially during the seedling stage. To determine the effect of early season P. cruciferae infestation on seed yield, 10 genotypes from each of two canola species (Brassica napus L. and Brassica rapa L.) and two mustard species (Brassica juncea L. and Sinapis alba L.) were grown in 2 yr under three different P. cruciferae treatments: (1) no insecticide control; (2) foliar applications of endosulfan; and (3) carbofuran with seed at planting plus foliar application of carbaryl. Averaged over 10 genotypes, B. rapa showed most visible P. cruciferae injury and showed greatest yield reduction without insecticide application. Mustard species (S. alba and B. juncea) showed least visible injury and higher yield without insecticide compared with canola species (B. napus and B. rapa). Indeed, average seed yield of S. alba without insecticide was higher than either B. napus or B. rapa with most effective P. cruciferae control. Significant variation occurred within each species. A number of lines from B. napus, B. juncea, and S. alba showed less feeding injury and yield reduction as a result of P. cruciferae infestation compared with other lines from the same species examined, thus having potential genetic background for developing resistant cultivars.

Population Genomic Analysis Reveals Differential Evolutionary Histories and Patterns of Diversity across Subgenomes and Subpopulations of Brassica napus L.

The allotetraploid species Brassica napus L. is a global crop of major economic importance, providing canola oil (seed) and vegetables for human consumption and fodder and meal for livestock feed. Characterizing the genetic diversity present in the extant germplasm pool of B. napus is fundamental to better conserve, manage and utilize the genetic resources of this species. We used sequence-based genotyping to identify and genotype 30,881 SNPs in a diversity panel of 782 B. napus accessions, representing samples of winter and spring growth habits originating from 33 countries across Europe, Asia, and America. We detected strong population structure broadly concordant with growth habit and geography, and identified three major genetic groups: spring (SP), winter Europe (WE), and winter Asia (WA). Subpopulation-specific polymorphism patterns suggest enriched genetic diversity within the WA group and a smaller effective breeding population for the SP group compared to WE. Interestingly, the two subgenomes of B. napus appear to have different geographic origins, with phylogenetic analysis placing WE and WA as basal clades for the other subpopulations in the C and A subgenomes, respectively. Finally, we identified 16 genomic regions where the patterns of diversity differed markedly from the genome-wide average, several of which are suggestive of genomic inversions. The results obtained in this study constitute a valuable resource for worldwide breeding efforts and the genetic dissection and prediction of complex B. napus traits.

Resistance of canola-quality cultivars of yellow mustard, Sinapis alba L., to the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham)

Oilseed Bassica is susceptible to attack by the cabbage seedpod weevil while commercial yellow mustard, Sinapis alba L., is resistant. The objective of this study was to determine if canola-quality S. alba would maintain its resistance traits. In laboratory choice and nochoice tests we found the number of eggs laid by the weevil to be low or non-existent in all S. alba genotypes. Key words: Ceutorhynchus obstrictus, Ceutorhynchus assimilis, Sinapis alba, plant resistance

Cabbage seedpod weevil resistance in canola (Brassica Napus L.) yellow mustard (Sinapis alba L.) and canola × yellow mustard hybrids

Canola, yellow mustard and yellow mustard × canola hybrids were screened for resistance to Ceutorhynchus obstrictus (Marsham) in a series of greenhouse and laboratory choice tests. Tests were conducted using small and large cages designed to hold Brassica pods or whole plants, respectively, with ovipositing female C. obstrictus. Pods were examined for feeding punctures, eggs laid and exit holes that resulted from emerging larvae. All yellow mustard cultivars examined were highly resistant to C. obstrictus feeding and egg laying. In addition, hybrid lines were found with significantly reduced feeding punctures, oviposition, and exit holes compared with canola. A negative relationship was observed between total glucosinolate content of seed and C. obstrictus resistance; however, in both detached pod and whole plant choice tests, hybrids were identified with high seed glucosinolate content that were more susceptible than the most susceptible canola. The relatively poor association between total seed meal glu...

Detection of canola flowering using proximal and aerial remote sensing techniques

In plant breeding, the time and length of flowering are important phenotypes that determine the seed yield potential in plants. Currently, flowering traits are visually assessed, which can be time-consuming, less accurate and subjective. To address this challenge, in this study, proximal and remote sensing with an unmanned aerial vehicle (UAV) were applied to monitor the canola flowers in a breeding trial with 35 varieties. Visible digital images (RGB) acquired were processed to extract the flowering features. The results indicated that flowering features extracted from both proximal and aerial images were significantly and positively correlated (P < 0.0001) with each other and with visual ratings. In general, aerial imaging overestimated canola flowering rates, which could be resulting from lower resolution at measured altitude (30 m), and rendered lower correlation coefficients (r = 0.53 – 0.62) with visual ratings. Proximal sensing resulted in better estimation of canola flowering with r ranging from 0.65 to 0.91. This study indicated that remote sensing can be used for high-throughput phenotyping of canola flowers with confidence. High-throughput phenotyping techniques will potentially improve the throughput and objectivity of detecting flowers in canola and other crops, and contribute to the development of new cultivars in breeding programs and yield estimation in precision agriculture.