Brassica Napus Ssp Research Articles

Milk production responses, rumen fermentation, and blood metabolites of dairy cows fed increasing concentrations of forage rape (Brassica napus ssp. Biennis)

The aim of this study was to determine animal performance, rumen fermentation, and health-related blood metabolites of dairy cows in mid lactation fed with increasing levels (30 and 45%) of forage rape (FR) in the diet. Twelve pregnant multiparous lactating Holstein-Friesian dairy cows were randomly allocated to 1 of 3 dietary treatments in a replicated 3 × 3 Latin square design. The experiment was divided into three 21-d periods. For the control diet, 13.0 kg (dry matter, DM) of grass silage, 3.0 kg DM of commercial concentrate, 2.7 kg of DM cold-pressed extracted canola meal, and 0.45 kg DM of solvent-extracted soybean meal were offered daily. For the other two treatments, 30 and 45% of the DM from silage, canola meal, and commercial concentrate were replaced in equal proportions with FR. Data were analyzed individually using linear and quadratic orthogonal polynomials. Ingestive behavior was altered by the inclusion of FR. We observed a linear increase in eating time at the expense of rumination time. Nevertheless, total DM intake was not affected by dietary treatments, averaging 19.5 ± 0.24 kg of DM/d. Milk yield increased linearly with increasing concentration of FR in the diet. Thus, feed efficiency of cows (kg of milk/kg of DM intake) increased linearly with the percentage of FR in the diet. Inclusion of FR in the diet had no effect on milk composition or milk sensory characteristics. Mean rumen pH of cows decreased linearly from the control to the 45% FR diet; however, dietary treatments had no effect on the daily amount of time that rumen pH was below 5.8 (252 ± 71.4), indicating no risk of subacute ruminal acidosis. Concentrations of total volatile fatty acids in the rumen and molar proportions of acetate and butyrate were increased with FR inclusion, whereas the proportion of propionate was linearly reduced. Excretion of uric acid and total purine derivatives tended to be greater for cows fed FR, which resulted in a trend toward a linear increase in estimated microbial N flow. However, N use efficiency was not affected by FR inclusion. Although differences for some hematological measures (increased white blood cell and neutrophils counts) and a quadratic response for glutamate dehydrogenase for cows fed FR in the diet (decreased with inclusion of 30% and increased with 45% in the diet) were observed, all values were within appropriate ranges for dairy cows. These results indicated that including FR to dairy cow diets, up to 45% of diet DM, improved milk production due to changes in volatile fatty acids and predicted microbial N flow and had no negative effects on dairy cow health or sensory characteristics of milk.

Improved PCR-based assays for pre-symptomatic diagnosis of light leaf spot and determination of mating type of Pyrenopeziza brassicae on winter oilseed rape

An existing PCR-based method for diagnosis of the winter oilseed rape (Brassica napus ssp oleifera) fungal pathogen Pyrenopeziza brassicae (cause of light leaf spot) was improved by the development of a pair of primers (PbN1 and PbN2) for use in nested-PCR reactions. The nested-PCR technique improved the detection of P. brassicae DNA in vitro by three orders of magnitude over that achieved using the first-round PCR primers (Pb1 and Pb2). In controlled environment experiments, the nested-PCR assay detected P. brassicae within infected B. napus leaves before visible light leaf spot symptoms developed and earlier than was possible by incubating infected leaves in polyethylene bags to promote sporulation of P. brassicae. A three-primer PCR technique using the primers PbM-1-3, PbM-2 and Mt3 was developed to distinguish between the two mating types (MAT-1 and MAT-2) of P. brassicae. This technique was able to determine the mating types present within DNA extracted from infected plant tissue, including tissue infected with both mating types together.

Diversification of existing rice (Oryza sativa)-based cropping system for sustain- able productivity under irrigated conditions

A field experiment was conducted during 1998-99 and 1999-2000 at Palampur, to diversify existing rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system. Wheat in rice-wheat sequence was replaced with 1 or 2 crops of oilseeds or vegetables crops, viz. gobhi sarson (Brassica napus ssp oleifera DC var. annua L.), linseed (Linum usitatissimum L.), toria [Brassica campestris L. ssp. oleifera (Metzger) Sinsk. var. toria] potato (Solanum tuberosum L.), pea (Pisum sativum L.) and Frenchbean (Phaseolus vulgaris L.). Rice-pea-po- tat0 sequence recorded significantly highest rice-equivalent yield with production efficiency as high as 58.38 kg/ hdday. However, rice-pea-Frenchbean gave an additional net returns of Rs 7,1101ha over rice-pea-potato, which were also highest than that of rice-wheat. Land-use efficiency as well as benefit : cost ratio were also highest in rice-pea-Frenchbean. Thus in rice-wheat system, wheat crop can be safely replaced by pea, which can be fol- lowed either by potato or Frenchbean.

Integrated nutrient management in maize (Zea mays)-gobhi sarson (Brassica napus ssp oleifera var. annua) cropping system under rainfed condition

An experiment was conducted during 1998-99 to 2000-01 to work out an integrated nutrient management schedule for maize (Zea mays L.)-gobhi sarson (Brassica napus ssp oleifera var annua) cropping system under rainfed conditions. The total grain production was higher (110.5 qlha) when both crops in system were given 150% of recommended NPK and was 28 and 26% higher over recommended fertilizer application in maize and gobhi sarson respectively. However, an application of 150% of recommended NPK to maize and 100% NPK + 10 tonneslha farmyard manure (FYM) to gobhi sarson also resulted in statistically similar grain yield (108 qlha). Ap- plication of 10 tonnes FYM along with 100% NPK either to one crop or both crops increased the system produc- tivity by 7.7% over 100% NPK, application only. The N,P and K uptake in system was higher when both crops in system were given 150% NPK, followed by 100% NPK + 10 tonnes FYMIha application. Higher gross returns (Rs 75,251) and benefit : cost ratio (2.68) were obtained when both crops in system were given 150% of recom- mended NPK. Application of recommended NPK to both crops although gave lower gross returns (Rs 56,786), the benefit : cost ratio of 2.18 was most practical under limited resources.

Lack of interplot competition in Swedes (Brassica napus ssp rapifera L.)

An experiment comparing double row plants with four row plots where only the centre two rows were harvested (‘guarded double row plots’) were laid out in two subsequent years. Fresh weight yields, dry matter yields, ‘bulb’ dry matter content, refractometer index and harvest index were recorded and analyzed statistically. The cultivar x plot type interactions were in none of the cases significant. The increase in error variances when comparing double row plots with guarded double row plots was significant only for harvest index in the first year. Taking into account the low selection intensity when small plots are used, i.e. in early stages of plant breeding programmes, we conclude from these experiments that guarded plots are not necessary when breeding swedes under our growing conditions.

Effect of cultivar and harvest date on the glucosinolate and s‐methylcysteine sulphoxide content of swedes (Brassica napus ssp rapifera)

AbstractEighteen plants of each of four cultivars and two inbred lines of swede (Brassica napus ssp rapifera L) were harvested at monthly intervals from 25 July 1988 to 6 March 1989 and divided into leaf and bulb (swollen hypocotyl). On average, the yield per plant of bulb dry matter increased from 51 g to 277 g on 14 November and then slowly fell to 241 g, whereas that of leaf dry matter decreased from 81 g to 17 g on 9 January and then rose to 32 g. Bulb S‐methylcysteine sulphoxide concentration increased from 5.9 g kg−1 DM to over 9.4 g kg−1 from 14 November to 9 January and then fell to 7.3 g kg−1. Leaf SMCO concentration rose from under 5 g kg−1 DM to over 27g kg−1 on 6 February and then fell to 17 g kg−1. Bulb glucosinolate concentration was 11.2 mM kg−1 DM on 25 July, then fluctuated between 7.9 and 6.5 mM kg−1 before falling below 5.0 mM kg−1 on 6 February. Leaf glucosinolate concentration rose from under 4 mM kg−1 DM to over 37 mM kg−1 on 6 February and then fell to 28 mM kg−1. All cultivars showed these patterns despite some statistically significant cultivar × harvest date interactions. There were large and consistent differences between cultivars in glucosinolate composition. The implications for swede breeding are discussed.

Sugar content of swedes for stockfeeding

AbstractThe sugar content was determined of 19 cultivars of swede (Brassica napus ssp rapifera L) grown in rows 50 and 75 cm apart. Sugar concentration ranged from 54.3 to 78.7 g kg−1 fresh weight and was positively correlated with dry matter content which ranged from 90.4 to 138.7 g kg−1 fresh weight. The average concentration of fructose, glucose and sucrose in the dry matter was 225.0, 328.4 and 34.5 g kg−1 DM, respectively. The high‐dry‐matter cultivars tended to have less fructose and more sucrose than the low‐dry‐matter ones, but total sugar concentration in the dry matter was not associated with dry‐matter content. Row width had little effect on sugar content compared with the differences between cultivars. The implications for the feeding value of swedes are discussed.

Effect of cultivar and harvest date on dry‐matter content, hardness and sugar content of swedes for stockfeeding

AbstractEighteen bulbs of each of four cultivars and two inbred lines of swede (Brassica napus ssp rapifera L) were harvested at monthly intervals from 25 July 1988 to 6 March 1989. On average, dry‐matter yield increased from 50.8 to 277.0 g plant−1 by 14 November and then slowly fell to 240.5 g plant−1 on 6 March; and dry‐matter content rose from 99.5 to 118.9 g kg−1 fresh weight on 19 September and then slowly declined to 99.0 g kg−1 fresh weight in March. Hardness also increased from 25 July to 19 September but then remained constant. A hard high‐dry‐matter line, BWc4hca, and a soft lowdry‐matter line, CRdagaa, were the extremes for changes in sugar content. From July to October the average contents in g kg−1 DM of BWc4hca and CRdagaa were respectively: fructose 146.8, 224.3; glucose 206.8, 293.7; and total 390.7, 543.9. In contrast, from November to March their contents were much closer: fructose 187.9, 209.9; glucose 314.7, 323.I; and total 534.4, 549.3. Sucrose levels were much lower and more variable, but overall BWc4hca was highest, 34.1, and CRdagaa lowest, 20.6. The implications for swede breeding are discussed.

The effect of turnip mosaic virus infection on the mineral content and storability of field‐grown rutabaga

Abstract This study examined the influence of turnip mosaic virus (TuMV) on rutabaga (Brassica napusssp. rapifera (Metzg.) Sinsk) root yield, mineral composition and storability from plants infected during the late stages of first year growth. TuMV‐infected plants from four commercial fields in Ontario, Canada were sampled when one‐sixth to one‐fourth of the plant foliage displayed TuMV symptoms. TuMV was detected in the roots of infected plants but at. low levels. Root yield, root dry matter percentage and the elemental composition of roots were similar from TuMV non‐infected and infected plants in the same field. Nitrogen, ?, ?n and Zn contents in the root tissues were observed to vary among the fields. There was no obvious differences in storability between TuMV non‐infected and infected roots after 5 months at 1°C and 87% humidity

Resistance of leaves of Brassica species to Leptosphaeria maculans

Under controlled conditions, the range of responses in Brassica napusssp. oleiferaand its two putative parents, B. rapa and B. oleracea, were tested by inoculating leaves with a mixture of eight isolates or two separate isolates of Leptosphaeria maculons. Infection resulted in a hypersensitive reaction, or localized lesions of various sizes, or systemic colonization of the lamina and petiole. Although not apparently associated with hypersensitive resistance, levels of alkenyl glucosinolates in leaves were inversely correlated with lesion extension. The value and limitations of these various sources of resistance in breeding lines of B. napus ssp. oleifera are discussed.

Stability of Chloroplastic Triazine Resistance in Rutabaga Backcross Generations

Triazine resistance originally observed in a weed biotype of birdsrape (Brassica campestris L.) has been transferred through cytoplasmic substitution into rutabaga (Brassica napus ssp. Rapifera [Metzg.] Minsk.) by conventional backcrossing. Photosynthetic function and resistance to triazines were examined in six backcross generations of rutabaga as well as in the original parents. Chloroplast thylakoid membranes were isolated and their sensitivity to atrazine, metribuzin, and diuron assayed by measuring the inhibition of photoreduction of 1,6-dichlorophenol indophenol as well as the alteration of in vitro chlorophyll fluorescence rise characteristics. Both assay methods indicated that triazine resistance persisted in all rutabaga backcross generations, and that it involved triazine binding sites in chloroplasts. There was little resistance to diuron. In vivo chlorophyll fluorescence was also monitored, in the absence of herbicides, as an indicator of the electron transfer properties of the chloroplast photosystem II complex. The results indicated that electron transport from Q(A) to Q(B) was slower (as indicated by a larger intermediate level fluorescence during the transient rise) in the triazine resistant parents as well as in all the rutabaga backcross generations.

USE OF GIBBERELLIC ACID TO HASTEN FLOWERING IN RUTABAGA

In field conditions, rutabaga (Brassica napus ssp. Rapifera (Metzg.) Sinsk.) plants are biennials and require exposure to low temperature for completion of their life cycle to seed production state. When young rutabaga plants were thermoinduced (3–5 °C) for 8 wk and subsequently transferred to growth room conditions, formation of flower buds resulted in 6 wk. Flowering response was greatly enhanced if the plants were sprayed with GA3 (100 mg/L) prior to thermoinduction. Compared with untreated plants, the GA3-sprayed plants responded with flower bud formation after as little as 3 wk of cold treatment. A longer cold exposure (6–8 wk) of the GA3-sprayed plants resulted in rapid development and maturity of the inflorescence. This note emphasizes the pharmacological role of gibberellins as regulators of flowering and their usefulness to enhance seed production and plant breeding programs.

Self-pollination in swedes (Brassica napus ssp Rapifera) and its implications for cultivar production

The degree of selfing on open pollination was examined in four swede cultivars. Three cultivars had over 80 per cent selfing, whilst the fourth had less than 55 per cent. The inbreeding coefficient with these levels of selfing, assuming the cultivars were at equilibrium, would be 0.69 and 0.37 respectively. The cultivar with the high level of outcrossing was found to possess a degree of self-incompatibility. The structure of such populations is demonstrated, and the implications for cultivar production are discussed.

The production of F1 hybrid swedes (Brassica napus ssp. Rapifera) by the utilisation of self-incompatability

Six inbred lines from a swede with naturally occurring self-incompatibility were each isolated with a swede cultivar containing marker genes. The percentage of intervarietal hybrids produced by the self-incompatible lines was between 97.4% and 99.6%, whereas in the self-compatible marker cultivar it varied between 7.2% and 26.8%. The F1 hybrids showed increases in dry matter yield of 11.5% to 28.8% over the higher parent.