Canola and mustard response to short periods of high temperature and drought stresses at different growth stages

Non-Peer ReviewedBrassica crops grown on the semiarid Canadian prairie are often subject to heat and water stress during the period of flowering. A growth chamber study was conducted at Swift Current to understand the effects of short periods of high temperature stress and/or water stress at different developmental stages on the seed yield formation of different Brassica species. Two advanced breeding lines of canola quality Brassica juncea (PC98-44 and PC98-45) along with a canola cv. Quantum (B. napus L.) and a mustard cv. Cutlass (B. juncea L.) were grown under 20/18 °C day/night temperature. High (35/18 °C) and low (28/18 °C) temperature stresses were imposed for 10 days at bolting, flowering or pod formation stages in two separate growth cabinets. At the same time, low (90% available water) or high (50% available water) water stress was imposed on half of the plants in each of the temperature treatments. All yield components were affected by temperature stress, while water stress had no effect on most yield components. The severe reduction of pods main shoot-1 (75%), seeds pod-1 (25%), and seed weight (22%) by 35/18 °C, reduced main stem seed yield of by 87% in all Brassica cultivars. However, seed yield reduction per plant by the same stress was 51%, indicating recovery from the stress treatments by Brassica species. Delaying exposure to stress to pod development stage reduced the chance of the plant to recover from the stress. The low water stress was to encouraging better recovery at 28/18 °C stress. In the controlled growth chamber, B. juncea cultivars responded to heat stress by increasing pod production but ignoring filling pods, while B. napus maintained a better seed fill. Under field conditions where plant-to-plant competition is strong, B. juncea may produce more pods with higher seed yield than canola; this needs to be confirmed with further field trials

Measurement of water use by canola with sap flow gauges

Non-Peer Reviewe

Stubble and seeding management to improve microclimate and seed yield of canola

Non-Peer ReviewedThe benefit of standing stubble for wheat and pulse growth and yield is dependent upon the height of the stubble. Taller stubble traps more snow and creates a better microclimate for seedlings growth than short or cultivated stubble. Since information on the effect of stubble management on the in-crop microclimate of canola was lacking, a three year field study was conducted at Swift Current. Short (15cm) and tall stubble (30cm) effect on microclimate and seed yield were compared with that of cultivated stubble. The microclimate parameters included wind velocity, soil, air, and plant temperatures, solar radiation, and relative humidity. Microclimate observations indicated lower wind speed near the soil surface and lower soil temperatures in tall compared to cultivated stubble. Surprisingly, the stem temperature of canola seeded in tall stubble was higher than cultivated stubble. Biomass production and water use efficiency increased for tall standing stubble compared to cultivated stubble. Tall stubble increased mean seed yield by 9 and 19% compared to short and fall cultivated plots, respectively. The results indicated that a combination of improved microclimate was responsible for the yield increase

Yield adjustment by canola under different plant populations in the semiarid prairie

Non-Peer Reviewe

Mustard is better suited to the warmer and drier semiarid prairie than canola

Non-Peer ReviewedCanola is a risky crop in the warm and dry semiarid prairie. Mustard is reported to be less susceptible to stress, although very little evidence is available to support this view. Nitrogen is the second most important factor limiting potential yield on the semiarid prairie. Therefore, a three year field study over 14 site years was conducted to compare the adaptability of different canola and mustard cultivars, with special interest in canola quality mustard, under low, normal and high risk levels of N. Differences in Brassica spp. were noticed for growth duration, biomass production, seed yield and yield parameters. Seed yield of Cutlass was 15 and 32% higher than Quantum and Maverick cultivars, respectively. Canola quality mustard, J90-4316 produced seed yield similar to Quantum, but was lower than Cutlass, suggesting further breeding to improve agronomic quality of J90-4316 is needed. Mustards produced higher pods per plant and lower seeds per pod and seed weight compared to Quantum, while the lowest pods per plant, seeds per pod and seed weights were observed in Maverick. All Brassica spp. responded to N application by increasing growth duration, biomass and seed and yield component production. However, availability of water limits response of some of the parameters to higher levels N application. N application reduced oil content, but overall oil yield increased with N application. Interaction between B. spp. and N application or environment was also observed. Thus, the results suggest that mustards, especially, cutlass is better adapted to semiarid prairie than canola cultivars

Water use and water use efficiency of field pea and chickpea under the semiarid Canadian prairie conditions

Non-Peer Reviewe

Rhizobium inoculant formulation and placement in lentil and chickpea in the semiarid Canadian prairies

Non-Peer ReviewedLentil and chickpea are the major pulse crops grown in western Canada, but little is known about the responses of these annual legumes to rhizobium inoculant formulation, placement, and their interaction to fertilizers under semiarid environments. A field study was conducted from 1999 to 2002 on a medium-textured soil at Swift Current and on a heavy clay soil at Stewart Valley, both in Saskatchewan. The objectives were to (i) determine the effects of rhizobium inoculation and fertilization on nodule formation, N2-fixation, and their impacts on growth, yield, and seed quality in chickpea and lentil, and (ii) develop recommendations for optimizing rhizobium inoculation, P-solublizing inoculation, and fertilizer N and P application for direct-seeding of chickpea and lentil with 1-, 2-, and 3-tank delivery systems. The results of the six site-years showed that use of rhizobium inoculation increased seed yield by 35% for desi, 7% for kabuli, and 23% for lentil. Inoculation reduced desi plant population by 10%, but not in kabuli or lentil. Granular inoculant increased yield by 7% in chickpea and 8% in lentil, compared to peat-based powder inoculant. Placement of granular inoculant (seed-row vs side-banding) had the same effect in all three pulses. Starter-N and starter-P at a rate of 15 kg ha-1 each had a marginal effect on plant growth and seed yield, but a higher rate of P (34 kg P2O5 ha-1) increased kabuli seed size. Chickpea and lentil did not show any response to Penicillium bilaii (fungus contained in the products JumpStart® and TagTeam®) under the semiarid growing conditions

Effect of stubble microclimate on canola yield

Non-Peer ReviewedA field study using farm scale seeding and harvesting equipment was conducted to assess the effect of stubble management on the microclimate, water use and seed yield of canola at Swift Current on Swinton Silt Loam. The differences in wind velocity, soil temperature and solar radiation reaching soil surface indicate significant modification of microclimate by tall stubble compared to cultivated plots. Stubble management did not influence biomass production and water use. But tall stubble significantly increased seed yield and water use efficiency over other stubble treatments. Seeding dates interacted with stubble treatments. The results suggest that, early or fall seeding may be better to exploit the potential of tall stubble. Thus tall stubble has a great potential in the heat and water stressed semiarid prairie

Seeding management to reduce temperature stress in Brassica species

Non-Peer ReviewedFall seeding is a promising new technology for canola production in the prairie. A field trial was conducted to extend this technology to the semiarid prairie, where at least some drought and heat stress is expected routinely. The objective was to see whether fall seeding is better suited to all oilseed Brassica species. Fall seeding advanced growing season and flowering in all B. species. Fall seeded crops were less stressed due to heat or water shortage. Species and seeding dates influenced seed yield. Early spring seeding was higher yielding than fall seeding due to large yield decline observed in Polish canola and mustard (8 to 30%) due to fall seeding, while the same decline in Argentine canola was only 1-9%. However, delaying seeding to late spring reduced yield significantly in all three species. The result needs to be confirmed under hotter and drier season

Effect of high temperature stress on yield and yield components of three brassica species

Non-Peer Reviewe