Osmotic adjustment segregates with and is positively related to seed yield in F3 lines of crosses between Brassica napus and B. juncea subjected to water deficit

2006 ◽  
Vol 46 (12) ◽  
pp. 1621 ◽  
Author(s):  
Q. Ma ◽  
D. W. Turner

For osmotic adjustment to be used as a selection criterion for adaptation to drought there is a need to demonstrate its segregation and association with seed yield in a population. This study examined osmotic adjustment and seed yield in F3 lines derived from crosses between Brassica napus (cvv. Karoo, Monty) and B. juncea (line JN25). A clear separation of the level of osmotic adjustment was observed among 20 F3 lines of Karoo × JN25 (7 high and 13 low) and 20 F3 lines of Monty × JN25 (8 high and 12 low) under glasshouse conditions. When the 3 parents and 8 selected F3 lines were grown in a low-rainfall environment in the field, the segregation of osmotic adjustment was largely similar to that observed in the glasshouse. Yield reduction, with irrigated plots as controls, was up to 30% for genotypes with low osmotic adjustment but only 10% for those with high osmotic adjustment. Osmotic adjustment was closely correlated with the accumulation of K+ (r = 0.91), soluble sugars (r = 0.90) and proline (r = 0.96), whereas other solutes (Na+, NH4+, Cl–, NO3–, Mg2+ and Ca2+) made little or no contribution to osmotic adjustment. Proline concentrations were very low in well-watered plants but sharply increased by 5- to 15-fold in plants subjected to water deficit, and net proline accumulation showed a higher association with total seed number (r = 0.86) and yield (r = 0.89) than did the concentrations of K+ (r = 0.75 to 0.82) or soluble sugars (r = 0.68 to 0.72). The study suggests that leaf proline concentration could be a good indicator of osmotic adjustment in Brassica oilseeds.

2006 ◽  
Vol 57 (2) ◽  
pp. 221 ◽  
Author(s):  
Qifu Ma ◽  
Sharon R. Niknam ◽  
David W. Turner

Canola (Brassica napus L.) is a major rotation crop but low yield has limited its adoption by farmers in the low-rainfall regions of southern Australia, where drought events can occur at any stage of crop development. We examined the effect of soil water deficit on osmotic adjustment and seed yield of canola and mustard (B. juncea L.) at the juvenile, elongation, anthesis, or seed-fill stage under glasshouse conditions and post-anthesis drought in the field. At the juvenile and elongation stages, leaves of both canola cv. Monty and mustard line 397-23-2-3-3 adjusted osmotically after exposure to water deficit. In comparison, only the mustard line expressed osmotic adjustment at anthesis and neither genotype adjusted at the seed-fill stage. A single drought event at the juvenile or elongation stage had little effect on growth and seed yield of either genotype, whereas water deficit at anthesis or seed-fill stage reduced seed yield of the canola cultivar by decreasing pod number, seeds per pod, and/or harvest index but largely did not affect the mustard line. In the field where rainfall diminished and plants were subjected to increasing water deficit during the reproductive stages, canola cv. Karoo and mustard line JN25 showed higher osmotic adjustment at anthesis and less yield reduction than the canola cv. Monty. This study suggests that yield sensitivity to water deficit was mainly due to its effect on concurrent formation of yield components, but could be modified by the physiological trait of osmotic adjustment.


2004 ◽  
Vol 55 (9) ◽  
pp. 939 ◽  
Author(s):  
Qifu Ma ◽  
David W. Turner ◽  
David Levy ◽  
Wallace A. Cowling

To establish methods for improving drought tolerance in Brassica oilseeds, we examined the influence of soil water deficit on solute accumulation in expanded and expanding leaves. We assessed the contribution of individual solutes to osmotic adjustment (OA) and determined the effect of homozygosity on the variation of the expression of OA. Juvenile plants of canola (Brassica napus cvv. Karoo and Monty) and Indian mustard (B. juncea line PI-81792) were grown under glasshouse conditions. The 3 genotypes expressed similar magnitudes of OA in response to drought, compared with a 2-fold higher OA in expanding leaves than in fully expanded leaves. Drought-induced changes in OA of expanded leaves of all genotypes were largely due to the accumulation of nitrate (42−47%), soluble sugars (31−38%), and proline (11−14%). In expanding leaves, K+ accumulation was significant (23–27%) as was proline (17−22%), whereas nitrate and soluble sugars were less important than in expanded leaves. By comparison, ions of Na+, Cl–, and water-soluble Mg2+ and Ca2+ did not contribute significantly to OA. Proline was hardly detected in well watered plants, but sharply increased in leaves of droughted plants in direct proportion to the magnitude of OA (80 ± 7 mmol/MPa, r2 = 0.94). A comparison between doubled haploid (DH) and commercial seed sources of 2 B. napus cultivars showed similar mean values in OA. The DH lines had a 33% lower coefficient of variation in OA than cv. Karoo and 48% lower than cv. Monty among replicate plants. Proline may be a suitable ‘marker’ for OA in juvenile Brassica plants because of all the solutes measured, its concentration was directly proportional to the magnitude of OA across cultivars and leaf types. The use of DH lines will improve the precision in selection of genotypes that have the capacity to osmotically adjust under soil water deficit.


Hoehnea ◽  
2019 ◽  
Vol 46 (4) ◽  
Author(s):  
Rodrigo Fazani Esteves Sanches ◽  
Ana Paula Oliveira da Silva ◽  
Vanessa Pires da Costa ◽  
Maria Ângela Machado de Carvalho ◽  
Emerson Alves da Silva

ABSTRACT Water stress is an environmental factor that can regulate growth, limit production and lead to physiological and biochemical changes. Plants present a series of adaptive responses to drought, such as osmotic adjustment, in which carbohydrates play an important role. To evaluate the influence of water deficit on carbohydrates accumulation in V. discolor, the plants were divided into two groups: daily watering and water suppression for 14 days being re-watering after this period. Leaves and roots were collected at 0, 3, 6, 9, 12, 15 and 18 days, for ecophysiological and biochemical analyzes. Variations in carbohydrate contents in V. discolor showed a close relationship with changes in the plant water status, with higher concentrations of soluble sugars, total fructans, oligosaccharides, reducing sugars coinciding with the lower values of soil moisture and leaf water potentials and relative water content. In the tuberous roots, there is an increase in carbohydrate concentrations after re-watering. The increase of these low molecular weight carbohydrates is involved in osmotic adjustment and therefore acts to protect against dehydration.


1990 ◽  
Vol 70 (3) ◽  
pp. 611-618 ◽  
Author(s):  
R. PINNISCH ◽  
P. B. E. McVETTY

Hybrid summer rape (Brassica napus L.) seed production blocks were established at two locations in Manitoba in 1986 and 1987 to examine the effect of distance from the pollen source on seed yield, (both total and hybrid) and percent hybridity of seed produced on rows of a male sterile line of the open pollinated population B. napus cultivar, Marnoo, possessing the pol cytoplasmic male sterility inducing cytoplasm. A 10:1 ratio of male sterile line (A-line) to pollen parent was employed. Leaf cutter bees (Megachile rotundata F.) were used as the pollen vector between the two parents. In 1986, no significant differences in total seed yield were found among A-line rows, while in 1987, significant differences in total seed yields of A-line rows were found. Differences in hybrid seed yields among A-line rows were significant for all locations and years. Leaf cutter bees were found to be effective pollinators of the A-line plants. Less than half and less than a third of the seed produced on the A-line rows in 1986 and 1987, respectively, was hybrid seed. The high percentage of non-hybrid seed present in the seed lot may have been due to incomplete male sterility of the Marnoo A-line population. Total seed yields, hybrid seed yields and percent hybridity all declined linearly as distance from the pollen source increased. Improvement in the degree of male sterility of the Marnoo A-line population and/or a reduction in the 10:1 ratio of parents, and subsequent maximum A-line row to R-line row distance, will be necessary if hybrid summer rape seed production using this pol CMS A-line is to be commercially viable.Key words: Brassica napus L., CMS, hybrid, hybridity


1992 ◽  
Vol 118 (3) ◽  
pp. 301-308 ◽  
Author(s):  
A. M. Tommey ◽  
E. J. Evans

SUMMARYPatterns of assimilate distribution in single plants of winter oilseed rape (Brassica napus L.) cv. Mikado, following a reduction in sink capacity at flowering were investigated in two field experiments during the 1985/86 and 1986/87 growing seasons at Cockle Park Experimental Station, Northumberland. Plants demonstrated considerable compensatory growth following the removal of flowers from the terminal raceme and primary branches.Flower removal from lower branches did not significantly reduce total seed weight. Plants with a pod-bearing terminal raceme and one, two or three productive higher-order branches yielded a similar amount of seed. When seed production was confined to the terminal raceme and first four primary branches, seed yield per plant was greatly increased. Removal of flowers from the terminal raceme and uppermost branches of plants increased the number and productivity of lower-order branches but not enough to offset the overall loss in seed yield potential per plant. Indeed, when flowers were removed from higher-order racemes, the reduction in total seed weight per plant, was directly related to the degree of flower removal. The additional seed yield obtained from individual branches of modified plants in both experiments arose largely through an increase in fertile pod number and seed number per pod. Flower removal treatments did not greatly influence mean seed weight.The results clearly demonstrated that the loss of flowers from lower-order branches could be tolerated and may even be beneficial. Conversely, the removal of flowers from higher-order branches resulted in significant yield reductions. The production of lower branches should be restricted, therefore, in order to increase the superiority of the terminal raceme and uppermost branches and to increase the overall production efficiency of the crop canopy.


2016 ◽  
Vol 44 (1) ◽  
pp. 272-279 ◽  
Author(s):  
Sibgha NOREEN ◽  
Shakeela NOOR ◽  
Shakeel AHMAD ◽  
Fehmeeda BIBI ◽  
Mirza HASANUZZAMAN

Canola (Brassica napus L.) crop ranks third after soybean and palm among oilseed crops for production of vegetable oil and meal for human and livestock, respectively around the globe. The cultivars of canola crop vary greatly in their yield potential in response to eco-edaphic factors under different production environments. Therefore, research studies were undertaken to evaluate eight cultivars of canola crop ‘Shiralee’, ‘Dunkled’, ‘Bulbul-98’, ‘Ac-Excel’, ‘Cyclone’, ‘Rainbow’, ‘DGL’ and ‘Faisal Canola’ for quantifying some physiological and productivity indices  under normal growing conditions. The results showed that various cultivars of canola differed significantly amongst themselves with respect to biological yield, chlorophyll content, protein content, nutrient composition and components of seed yield. Among the cultivars, cvs. ‘Bulbal-98’ and ‘Rainbow’ produced maximum biological yield and seed yield,  respectively, Furthermore, maximum yield harvested from cv. ‘Rainbow’ was associated with higher total seed weight plant-1, while cv. ‘Faisal Canola’ maintained higher chlorophyll content than other ones. Cultivar ‘Dunkled’ contained higher K+ nutrient by 21.13 mg g-1 in leaf tissues compared to minimum (9.73 mg g-1) in ‘DGL’ cultivar. The higher amount of Na+ content (12.16 mg g-1) was determined in cv. ‘AC Excel’. Cultivar ‘Rainbow’ maintained higher photosystem (II) activity and had greater partitioning ability of photo-assimilates in the seed tissues. Of various chlorophyll fluorescence parameters, quantum yield of photosystem II and electron transport performance index could be used as a selection criterion for breeding of canola cultivars.


2013 ◽  
Vol 38 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Stanisław Flasiński ◽  
Janina Rogozińska

Water deficit affecting winter rape plants during flowering and seed formation caused metabolic responses characteristic for drought. Proline accumulation took place in the leaves, the inflorescences and in the siliques. Protein content during flowering and seed formation was reduced in all rape organs except leaves in the latter stage. The decrease of chlorophyll content in the leaves was greater during the period of seed formation than during flowering.


2020 ◽  
Vol 100 (6) ◽  
pp. 597-608
Author(s):  
Jonathan Vollmer ◽  
Burton L. Johnson ◽  
Edward L. Deckard ◽  
Mukhlesur Rahman

Natural hail can cause significant damage on seed yield and yield contributing traits of canola (Brassica napus L.). Hail damage can be assessed by (i) type of damage such as stand reduction, stem cut-off, and leaf defoliation, (ii) level of damage, and (iii) plant growth stage. In this research, a simulated hail study was performed by applying nonuniform stand reduction treatments on canola grown in North Dakota, USA, over 5 site-years, in 2017 and 2018. The experiment was a randomized complete block design 4 × 5 factorial arrangement with four growth stages, rosette, bolting, 50%, and 90% flowering, when five stand reduction treatments were applied at 0 (control), 25%, 50%, 75%, and 90%. Growth stage and stand reduction were significant for seed yield where yield decreased as stage of treatment progressed and level of stand reduction increased. Regression equations were developed to estimate the seed yield reduction at each growth stage as stand reduction increased. Stand reduction also affected other traits where plant height was reduced as stand reduction increased, whereas 1000-seed weight, primary branches plant−1, secondary branches plant−1, pods plant−1, seed yield plant−1, plant biomass plant−1, and harvest index plant−1 increased as stand reduction increased. As growth stage progressed the number of primary branches plant−1, secondary branches plant−1, pods plant−1, and harvest index plant−1 decreased, whereas 1000-seed weight increased. The findings of differential yield losses by stand reduction will help producers and crop adjusters to assess the severity of hail damage in canola.


2003 ◽  
Vol 43 (9) ◽  
pp. 1127 ◽  
Author(s):  
S. R. Niknam ◽  
Q. Ma ◽  
D. W. Turner

The relationship between osmotic adjustment and seed yield of Brassica oilseeds was examined at a low rainfall site, Merredin, Western Australia, in 1998 and 1999. Genotypes of B. napus and B. juncea were subjected to rain-fed and irrigated treatments at the seed-fill stage. The B. juncea lines showed small or even no yield reduction under rain-fed conditions, and generally had no yield advantage over the B. napus cultivars where irrigated. In both species, an inverse correlation was found between the magnitude of osmotic adjustment and the percentage of yield reduction. Genotypes with low osmotic adjustment, under rain-fed conditions, had a yield reduction of up to 40%, whereas those with high osmotic adjustment had only 0–10% yield reduction. In contrast, seed oil concentrations decreased from 41% under irrigation to 38% under water deficits and the differences among genotypes were not related to osmotic adjustment. In 1999, osmotic adjustment was again observed for most of the genotypes, but its association with seed yield was not as obvious as in the previous year and usually only the osmotically adjusting B. juncea genotypes maintained a good yield under water deficits. Not all the B. juncea genotypes expressed osmotic adjustment despite the fact that they were generally more drought resistant than the B. napus genotypes. In both years, however, osmotic adjustment was associated with increased harvest indices of B. napus and B. juncea, indicating that this physiological trait can be beneficial to Brassica yield in a water-limited Mediterranean-type environment.


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