Growth and Yields of Intercropped Sorghum and Sunflower (Helianthus annuus L.) in Semi-arid Nigeria

Effect of five planting patterns on the growth, yield and yield components of intercropped sunflower and sorghum was studied during 1989–90 planting seasons at University of Maiduguri, Nigeria. Generally, intercropping depressed the performance of sorghum more than sunflower. Sorghum plants grown in alternate hills with sunflower had the shortest stems, the least dry matter and total seed yields per hectare, while the highest dry matter and seed yields were obtained from sorghum planted in five alternating rows with sunflower. Similarly, in sunflower, plants grown in five alternating rows with sorghum had the highest yields compared with other planting patterns, but there were no significant differences in the dry matter and total seed yields of sorghum and sunflower intercropped in three and five alternating rows. Light transmission, leaf area index and yields of both crops followed similar trends under the various planting patterns. Interplanting in five alternating rows that allowed the highest leaf area also allowed the lowest light transmission and produced the highest yields. Land use efficiency was highly improved under three and five rows interplanting by 52 and 74 % respectively.     

Plant Regeneration and Genetic Variability from Tissue Cultures of Sunflower (Helianthus annuus L.)

Adventitious buds were induced from in vitro culture of sunflower (Helianthus annuus L.) cotyledons. Four inbred lines (G1, G2, G3 and HA89), an open pollinated variety (‘Argentario’) and two hybrids with specific genetic markers were used. Cotyledons were cultured in vitro on MS medium (Murashlge and Skoog 1962) containing various concentrations of kinetin and indole 3-acetic acid (IAA). The quantitative interactions between auxin and cytokinin, the age of the cotyledons and the 2,3,5-triiodobenzoic acid (TIBA) treatments have been found to influence shoot regeneration. The plantlets, after rooting, were successfully established on soil. Qualitative variation was noted in self-pollinated progeny of plants regenerated from culture of two inbreds. Chimerism in regenerated plants was indicated by sectoring of the genetic markers. Some culture-induced variant phenotypes were similar to known spontaneous mutation in sunflower but others have been not yet described. Preliminary data indicate that most of them may have single-gene recessive inheritance.     

Origin and Fate of Aneusomaty in Sunflower (Helianthus annuus L.)

Chromosomal variability in Helianthus annuus was studied during the ontogenetic cycle of the plant. Aneusomaty originates during embryo development, progressively decreases in the course of plant growth and disappears at pre-meiosis. A number of aberrant mitoses with lagging chromosomes were found in all embryonic stages examined; by contrast, mitoses never showed aberrations in the shoot apices of plants.     

向日葵细胞质雄性不育性的机制与利用

向日葵杂种生产采用三系配套系统完成。因此,向日葵细胞质雄性不育性的研究备受关注。其中研究较为清楚的是PET1细胞质,其不育机理是线粒体DNA重组形成嵌合基因,编码新的多肽,导致小孢子的败育。然而,这些基因如何影响小孢子发育的生理机制仍不清楚,有待进一步深入研究。丰富多样的向日葵CMS会大大降低因遗传单一性给大规模生产带来的风险;未发现恢复系的CMS可以用于无花粉观赏向日葵杂交种的生产。     

Environmental Effects on Seed Characteristics of Sunflower (Helianthus annuus L.)

Sunflower hybrid PARC-92E seed lots produced at Gider, Panjpai, Chilas, Fateh Jang and Dera Ismail Khan were compared for seed quality. 100-seed weight ranged from 5.38 to 7.29 g, oil content from 33.76 to 42.53%, hull–kernel ratio from 0.380 to 0.587, seed–kernel ratio from 1.64 to 2.62, germination potential from 97.50 to 100 %, germination rate index from 11.18 to 20.58, germination index from 13.45 to 17.92, emergence rate index from 51.61 to 145.40, and emergence from 57.96 to 84.82. 100-seed weight had a positive relationship with all the other parameters except oil percentage (−0.087). Seed size was found to be more important than oil content for field emergence of sunflower.     

Selective Postemergence Herbicides for Grass Control in Sunflower (Helianthus annuus L.)

Selective postemergence herbicides to control grass weeds in broadleaf crops have become available in recent years. However, the efficacy of these new herbicides in controlling grasses in sunflower has not been extensively evaluated. Field experiments were conducted to evaluate five selective herbicides for their efficacy on crabgrass ( Digitaria sanguinalis L. Scop) and barnyard grass ( Echinochloa crusgalli L. Beav.) control in sunflower ( Helianthus annuus L.) in 1983 and 1984. Commercial sunflower varieties, Interstate 7775 and Stauffer 3101 were planted on Calloway silt loam and Portland clay in 1983 and 1984, respectively. Herbicides were applied when sunflower was 10 cm tall, at 4- to 5-leaf stage, and target grass weeds at the 3- to 4-leaf stage. All herbicides, sethoxydim, xylofop-ethyl, haloxyfop, fluazifop butyl, and CGA 82725, gave good to excellent control of the target weeds. Herbicide injury to sunflower ranged from very minor to none. None of the herbicides greatly affected yield, test weight, seed weight, head diameter or plant height of sunflower. Difference in soil types tended to influence the effectiveness of herbicides.     

Photosynthesis as Influenced by Assimilate Level in Sunflower (Helianthus annuus L.)

The regulation of photosynthesis by its assimilates was investigated in sunflower by altering the assimilate level in leaves by girdling, detopping, shading and defoliation. The level of assimilates like sucrose accumulated in leaves did not inhibit photosynthesis or Rubisco activity. Starch levels also did not have an influence on the photosynthetic rate.     

Cytological Study of Callus and Regenerated Plants of Sunflower (Helianthus annuus L.)

In vitro culture of shoot apical meristems of Helianthus annuus was studied to determine the cytological condition of calli and regenerated shoots. A broad chromosome mosaicism (aneusomary) in bath callus and regenerated shoots was found, reflecting the cytological conditions of the explain. During in vitro plant development, a diplontic selection took place that was more rapid when very precocious in vitro flowering occurred.     

The Influence of Plant Water Stress on Net Photosynthesis and Yield of Sunflower (Helianthus annuus L.)

The effect of plant water stress on net photosynthesis, leaf growth, yield and yield-related components were investigated in a single experiment in order to determine in which way water deficits affect sunflower yields.
Sunflower plants, grown under controlled temperature regimes, were stressed during budding, anthesis and seed filling by withholding water until the leaf water potential reached -1600 and -2000 kPa. Leaf area of unstressed plants significantly exceeded that of plants under severe stress during all growth stages investigated. The CO₂ uptake rate per unit leaf area as well as the total uptake rate per plant, significantly diminished with stress, while this effect drastically increased during the reproductive phase of the plant. Although this resulted in significantly smaller heads and kernels, it did not affect the number of seeds borne in the inflorescence. Severe stress during anthesis and seed filling resulted in more empty kernels. Moderate and severe stress during budding significantly lowered both grain and oil yields while plants that experienced moderate stress during anthesis and seed filling significantly outyielded those under severe stress.     

Influence of Benzyladenine on Leaf Senescence and Photosynthesis in Sunflower (Helianthus annuus L.)

The effect of foliar application of benzyladenine on sunflower leaf senescence, photosynthesis, RuBP carboxylase activity and diffusion resistance was investigated. A considerable drop in photosynthetic rate and rise in diffusion resistance were noted dunng the seed filling period. Benzyladenine application maintained the chlorophyll content and chlorophyll a : b ratio at higher level, enhanced RuBP carboxylase activity and net photosynthesis in both upper and lower leaves. A lower level of diffusion resistance was also observed by benzyladenine application during seed filling period. The results suggested that application of benzyladenine at 30, 60 and 90 days after sowing could help to maintain photosynthesis and assimilate supply to the developing seeds of sunflower.     

基于DUS测试性状的向日葵品种遗传多样性分析

利用NY/T 2433-2013中的43个基本测试性状对巴彦淖尔分中心的63个向日葵参试品种进行遗传多样性分析,并与32个近似品种作比较,结果表明：参试品种表型性状中共检测到124个等位变异,平均每个性状检测到3.0244个,变幅为1~8个。Shannon’s多样性指数（H＇）平均值为0.5582,变幅为0~1.8101,41个有效测试性状中有17.07%的性状存在5个及以上等位变异,有51.22%的性状存在3个及以上等位变异,参试品种的等位变异数、每个性状的等位变异数及其变异幅度、多样性指数平均值等均大于近似品种。在外观形态上,参试品种的遗传多样性比近似品种更丰富。UPGMA聚类分析发现,在相似系数为0.860时,可将95个向日葵品种分为2个类群。主坐标分析结果与UPGMA聚类分析结果基本一致,但是可以通过向日葵品种在主坐标中的位置更加直观地判断95个向日葵品种间的遗传相似性。总体看来,参试品种与近似品种形态差异较小,建议育种家拓宽向日葵亲本选育材料,从而促进向日葵材料创新及新品种选育。     

Genotype Rankings for Nutrient Stress Resistance are Unrelated to Stress Severity in Cultivated Sunflower (Helianthus annuus L.)

Abiotic stress limits crop productivity worldwide, making stress‐resistant crops a major goal for improving food security. Stress resistance is often assessed by comparing genotypes under a single control and stressed level of an abiotic factor, then ranking the genotypes’ overall performance, using a metric like geometric mean productivity (GMP). However, abiotic stress is rarely a presence/absence phenomenon, but often varies continuously. Here, we tested whether the common practice of assessing performance using a single control and stress level is predictive of performance across a range of stress levels. Twelve sunflower genotypes were grown in the greenhouse under one of eight nutrient levels (from non‐limiting to severely limiting) and assessed for performance (shoot dry mass at the budding stage) and related traits at both seedling and budding stages. Contrary to expectations, genotype rankings for GMP were consistent regardless of the two nutrient levels used to calculate GMP. This suggests that, for nutrient stress in sunflower, studies using an arbitrary control and stress level are broadly representative: genotypes with high GMP exhibit high GMP regardless of the nutrient levels used. In addition, GMP values were highly correlated with performance in the respective nutrient levels from which they were calculated; thus, higher GMP for a given genotype indicates that it performed well (relative to other genotypes) under both stressed and non‐stressed conditions. Together, these findings strongly support the current paradigm of comparing genotypes at a single control and stress level as a valid strategy for screening for nutrient stress resistance in sunflower. However, few traits were consistently associated with performance (shoot dry mass) at either high‐ or low‐nutrient availability, and seedling traits were rarely predictive of budding‐stage traits and performance, suggesting further studies are needed to determine the mechanisms underlying nutrient stress resistance in this important oilseed crop.     

Effect of Phosphorus and Nitrogen Fertilization on Sunflower (Helianthus annus L.) Nitrogen Uptake and Yield

Little is known about the effect of combined phosphorus and nitrogen (P‐N) fertilization on the N requirement of sunflower (Helianthus annus L.). This study was carried out to evaluate the effects of varying levels of P and N, as well as the interaction P × N, on the N uptake, yield and N apparent utilization efficiency under field conditions. Split‐plot design experiments were conducted in the mid‐western Pampas in Argentina. Four levels of N (0, 46, 92 and 138 kg N ha^?1) and three levels of P (0, 12 and 40 kg P ha^?1) were applied to two Typic Hapludolls over two growing seasons (1997–98 and 1998–99). N uptake and soil N‐NO₃ contents were determined at the V₇, R₅ and R₉ growth stages. The sunflower yield ranged from 2.5 to 5.0 Mg ha^?1. The total N requirement was around 45 kg N Mg^?1 grain, and this result suggests that it is not necessary to use different N requirements (parameter b) for fertilized crops when a yield response is expected. To achieve a 100 % yield maximum a N supply (soil plus fertilizer) of 181 kg N ha^?1 at P₄₀ was needed. However, at P₀, the highest yield was about 80 % of the maximum yield with a N supply (soil plus fertilizer) of 164 kg N ha^?1. P application increased the apparent use efficiency of the supplied N.     

Inheritance of 'Hullability' in Sunflowers (Helianthus annuus L.)

Improvement of the feed value of sunflower seedmeal by hulling achenes before crushing is of economic importance and varieties with good ‘hullability’ (ease of hulling) would be economically significant. Knowledge of the genetics of this characteristic is therefore necessary. Studies of heritability were made on a factorial cross of six female and six restorer lines. Hullability was measured as the ratio of hull removed by a laboratory huller against the total quantity of hull in the achene. The genotypes studied showed a wide range of hullabilities. There were considerable environmental effects but only small interactions; correlations between results in different locations were significant. Additive genetic effects predominated, although there were some interactions between parental lines. Narrow-sense heritabilities were 0.73–0.85 for genotype means, 0.52 when calculated from individual plants, and 0.36–0.76 from parent-progeny regressions. Early selection based on progeny means or a combination of individual and progeny values would appear to be the best method of breeding for improved hullability of sunflower achenes.     

杂交油葵A15种子纯度的RAPD鉴定

从杂交油葵A15及其亲本中提取基因组DNA,用180个RAPD随机引物进行扩增,从中筛选出3个可将亲本和子代区分开的引物OPD09、OPD12和OPK12。OPD09产生亲本互补的特征带OPD09-1470bp、OPD09-870bp;OPD12产生母本特征带OPD12-1230bp,OPK12产生父本特征带OPK12-1540bp、OPK12-940bp,上述谱带均在子代中出现。以单引物(OPD09)和双     

Donor Plant Growth Conditions and Regeneration of Fertile Plants from Somatic Embryos Induced on Immature Zygotic Embryos of Sunflower (Helianthus annuus L.)

Immature zygotic embryos of the sunflower inbred line ‘Ha 300’, cultivated on a modified MS medium containing 6-benzyladenine and a high amount of sucrose, regenerated fertile plants via direct somatic embryogenesis. Plant regeneration from immature sunflower embryos is generally characterized by a relatively high experimental variability resulting from the interactions of multiple factors. We present here a study of some of the factors acting on the donor plants and their influence on the capacity to regenerate plants. Repeated experiments during a 2-year period with greenhouse-grown as well as field-grown plants led to the following conclusions: (i) The use of pesticides, unavoidable in the greenhouse, is compatible with routine regeneration of fertile plants, (ii) The plant growth retardants tested were useful for the production of healthy plants in the greenhouse and had no effect on the regeneration capacity.     

人工模拟盐、碱环境对向日葵种子萌发及幼苗生长的影响

以向日葵品种白葵杂6号为试验材料, 中性盐NaCl和Na₂SO₄混合模拟盐胁迫、碱性盐NaHCO₃和Na₂CO₃混合模拟碱胁迫(两者摩尔比均为9∶1), 设计各6种处理。研究盐、碱胁迫下种子萌发及幼苗形成的相关生理表现。结果表明, 种子能够萌发并成苗的最高盐胁迫强度是pH 6.98, 电导率为1.311 dS m^-1(培养介质的pH和电导率); 碱胁迫强度是pH 9.71, 电导率为0.360 dS m^-1。在能够成苗的盐碱条件下, 随着盐胁迫强度的增强出苗率、成苗率下降, 出苗时间明显延迟; 而随着碱胁迫强度的增加, 成苗率下降, 出苗时间并不延迟。同时随着盐碱胁迫强度的增强, 幼苗的各项生理指标均下降, 下降幅度以碱胁迫明显大于盐胁迫。试验结果证明, 盐胁迫和碱胁迫对白葵杂6号种子萌发及幼苗形成的影响机制不同, 向日葵在这两个阶段对盐碱两种胁迫的耐受能力及响应特点也不同。这一结论进一步证实了盐、碱胁迫是两种性质不同的胁迫。     

Variation in Salinity Tolerance in Sunflower (Helianthus annum L.)

Forty-five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l^?1 of NaCl₂+ CaCl₂ (1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance. In a further greenhouse experiment, the salinity tolerance of three tolerant (HO-1, Predovik, Euroflor) and two sensitive (SMH-24, 9UO-985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl^? and more K⁺ in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K⁺ versus Na⁺ selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt-affected field confirmed the greenhouse results of the selected accessions. This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl^?, high uptake of K⁺, and maintenance of high K:Na ratios and K⁺ versus Na⁺ selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt tolerance in sunflower.     

Retrotransposon-related genetic distance and hybrid performance in sunflower (Helianthus annuus L.)

Heterosis is a main force leading the development of the hybrid seed industry in sunflower. The purpose of this study is to evaluate if heterosis effects for morphological traits among sunflower hybrids can be related to differences in the repetitive component of the genome of parental lines. The assumption is that, at least for certain traits, heterosis results from mutations in the cis-regulatory elements of genes, largely related to retrotransposon insertions and/or removals. Our experimental approach consists of a correlation study between hybrid performance and retrotransposon-related genetic distances between inbreds. Six sunflower inbred lines of different origin were crossed in a half diallel fashion; comparing parental lines and hybrids, mid parent heterosis of F₁ hybrids was evaluated for six traits. We estimated the parental genetic distances between the six inbreds on data gathered by the inter-retrotransposon-amplified-polymorphism (IRAP) protocol. Different retrotransposons previously isolated in sunflower were targeted by 11 primer pairs designed on conserved LTR domains. As a control, genetic distances were also calculated using 86 genic SNPs. We analysed the correlation between the mid-parent heterosis for each of the six traits analysed and the genetic distance (calculated on data obtained by SNP or IRAP analyses) between the parental lines. Differences between parents showed to be largely related to variations in the retrotransposon component of the genome. Retrotransposon-related genetic distance between parents resulted to be larger than that related to genic SNPs, and significantly correlated to seed yield and, at a lesser extent, to plant height and stem diameter in hybrids. The hypothesis that variations in the repetitive component of the genome, especially LTR-retrotransposons, affect the displaying of heterosis is discussed.     

Partitioning of Biomass, N and S in Sunflower (Helianthus Annuus L.) by Nitrogen and Sulphur Nutrition

Response of sunflower ( Helianthus annuus L.) to sulphur applied ca. 0, 30, 90 and 150 mg kg^-1 and nitrogen applied ca. 0, 100 and 200 mg kg^-1 soil were studied on a Typic Camborthids in greenhouse. Nitrogen and S application had a significant (P < 0.01) main and interactive effect on seed yield and dry weight of leaves and stem. Cumulative N and S contents of sunflower seeds, stem and leaves were significantly (P < 0.01) affected by N and S application. Sulphur transport and accumulation in sunflower seeds was increased with S application. There were significant (P < 0.01) correlations between seed yield and N and S content of sunflower plants. Critical S concentration (%) in 60 days old plants was 0.36 for 95 % relative yield of the maximum. Application of 90 mg S kg^-1 with 200 mg N kg^-1 resulted in the highest seed yield and maximum total S and N contents in sunflower leaves, stem and seeds. Relative increase in sunflower seeds yield at higher levels of N and S was more than that of dry weight of stem and leaves.