Response of Root Branching and Shoot Water Potentials of French Beans (Phaseolus vulgaris L.) to Soil Moisture and Fertilizer Potassium

Extensive branching patterns of roots and the maintenance of adequate water within shoots enables plants to overcome water stress. However, information on the relationship between fertilizer potassium, root branching patterns and shoot water potentials of food legumes grown under different soil moisture regimes is scarce. Thus, an experiment was conducted in a phytotron to ascertain the effect of fertilizer potassium on root branching patterns and shoot water potentials of a popular tropical food legumes (Frenchbeans Phaseolus vulgaris L). The plants were grown in a sand medium with 0.1, 0.8 or 3.0 mM of potassium under a suboptimal and optima) soil moisture regime.
Root lengths and dry weights were enhanced by potassium, especially under a suboptimal soil moisture regime. The branching patterns changed due to potassium, where the numbers of second and third order roots increased under both soil moisture regimes, although the impact was greater in plants grown with low soil moisture. Plant water contents measured in terms of shoot water potential, relative water contents, rurgid weight: dry weight ratio and water uptake capacity were also increased by potassium. A positive relationship was observed between root branching patterns and water potentials with increasing potassium levels especially in plants grown under suboptimal soil moisture conditions. Shoot growth and nodulation was also promoted by potassium. The ability of plants to develop a more extensive branching pattern of roots by inducing a greater number of second and third order roots and changing the root branching habit from a herringbone to a dichotomous type to maintain a greater shoot water potential especially under low soil moisture regimes is presented.     

Effect of Soil Moisture and Potassium Fertilizer on Shoot Water Potential, Photosynthesis and Partitioning of Carbon in Mungbean and Cowpea

The effect of different rates of potassium (K⁺) on shoot water potential, photosynthesis and carbon movement (using ¹⁴C) at the V3/4 growth stages was studied in mungbean ( Vigna radiata L. Wilczek), a drought-susceptible legume, and cowpea ( Vigna unguiculata L. Walp), a drought-tolerant legume, grown under low- and high-irrigation regimes under controlled conditions. Soil moisture and K⁺ affected all measured parameters in the two species. The rate of photosynthesis was higher at reduced water stress when K⁺ was applied. The impact was greater in cowpea, which had an inherently high rate of carbon assimilation. Mungbean and to a lesser extent cowpea allocated greater quantities of carbon to roots under dry conditions, especially with added K⁺. The distribution of ¹⁴C into other plant parts was also increased at higher rates of K⁺ application under both soil moisture regimes. Thus, application of K⁺ seems to have a beneficial effect in overcoming soil moisture stress and increasing physiological parameters and carbon partitioning in these two important tropical food legumes.     

Root and Shoot Development of Phaseolus vulgaris L. (French Beans) as Affected by Soil Moisture and Fertilizer Potassium

The development of an extensive root system enables plants to overcome water stress. However, there is little information on the response of food legumes to soil moisture, especially during early growth, which determines crop establishment. Thus, an experiment was conducted under controlled conditions to identify the effect of soil moisture and fertilizer potassium on root and shoot growth of french beans ( Phaseolus vulgaris L.) seedlings. The seedlings were grown in a sand medium under a high and low soil moisture regime and with 0.1, 0.8 or 3.0 mM potassium.
Root lengths, dry weights and numbers of root hairs were greater under low soil moisture conditions. Potassium increased root growth irrespective of soil moisture regimes. The impact of potassium on root length was more pronounced under a high soil moisture regime. In contrast, potassium increased root dry weights and root hairs to a greater extent when plants were grown under dry conditions. The lack of adequate soil moisture increased specific leaf weights, and this phenomenon was reduced by the application of potassium. Shoot:root ratios also showed a similar phenomenon. The development of an extensive root system by french bean seedlings under dry conditions to extract a greater quantity of available soil moisture fur establishment and plant growth and the ability of potassium to promote this phenomenon is presented in this study.     

Growth and Yields of Cowpea (Vigna unguiculata (L.) Walp) as Influenced by Seed Characters, Soil Moisture and Season of Planting

Cowpea ( Vigna unguiculata L. Walp) is an important food legume grown under rainfed conditions in the tropics. However, the yield of this crop varies widely in most tropical ecosystems due to crop and environmental factors. Experiments were carried out to evaluate the effects of seed characteristics, soil moisture at planting and the season of crop establishment on growth and yield parameters of cowpea as these influence the productivity of the crop. Growth and yield of cowpea plants grown from small seeds with a high conductivity of their lea-chates were significantly lower than those grown from large seeds. Root growth of seedlings was most prominent under moderate soil moisture levels. Low soil moisture retarded root growth by reducing dry weights and suppressing the development of laterals. Shoot growth was more sensitive to increasing soil moisture stress than root growth. Planting cowpea in the wet season produced the highest yields. Within a season, growth and yield were higher when the crop was planted early. Establishment of the crop later in the season produced better quality seeds measured in terms of germination after controlled deterioration.     

Impact of Different Weed Types on Growth and Yield of Mungbean (Vigna radiata L. Wilczek)

The influence of different weed types (grass, broadleaved and sedge species) on growth and yield parameters of mungbean ( Vigna radiata L. Wilczek) was evaluated under field conditions. The presence of all types of weeks had the most significant effect on growth and yields of mungbean. Broadleaved species alone had a greater adverse effect than grasses, and the influence of sedges was the lowest. The adverse effect of weeds was most prominent on vegetative growth. The influence on yield components reduced with time. However, the adverse impact of weeds on yields was similar to that on vegetative growth. A significant correlation between weed biomass and yield loss was observed. The study indicated the critical competitive period to be in the vegetative phase. Some possible implications for selective weeding are presented.     

绿豆基因组SSR引物在豇豆属作物中的通用性

分子标记的种间通用性可降低其开发成本,提高利用效率,也有助于促进遗传研究较薄弱物种的分子遗传学研究。本文选取绿豆、小豆、豇豆及饭豆材料各3份, 分析1 205对新开发的绿豆基因组SSR引物在这些材料中的扩增效果,结果显示绿豆基因组SSR引物在豇豆、小豆和饭豆中的通用性比率分别为50.0%、73.3%和81.6%;多态性比率分别为4.1%、1.7%和1.5%;在4个种间均通用的引物469对。这些通用性SSR引物将有助于这4种食用豆类在多样性评价、连锁图谱的构建、基因定位及比较基因组学等方面的研究。     

Effects of Deficit Irrigation and Salinity Stress on Common Bean (Phaseolus Vulgaris L.) and Mungbean (Vigna Radiata (L.) Wilczek) Grown in a Controlled Environment

As water for irrigation purposes becomes increasingly scarce because of climate change and population growth, there is growing interest in regulated deficit irrigation (RDI) as a way to improve efficiency of water usage and farm productivity in arid and semi‐arid areas. Salinity is also becoming an important problem in these same regions. Experiments were performed to investigate the effects of RDI and salt stress on two legumes crops, common bean (Phaseolus vulgaris L.) and mungbean (Vigna radiata (L.) Wilczek); previous work showed contrasting responses to RDI by these two crops under field conditions. The seed and biomass yields of both crops were reduced as a result of increasing water deficit stress; however, mungbean was able to maintain the same proportion of its biomass in reproductive structures and maintain its harvest index under stress, whereas common bean’s decreased. In addition, photosynthesis in mungbean was higher than in common bean and higher at the same levels of transpiration. Finally, salinity stress did not affect the water potential, harvest index or the specific leaf weight of either crop. There were no interactions between salinity and crops or RDI levels, which suggest that the two crops do not differ in their response to salinity stress, and that RDI levels do not modify this response.     

Effect of Method of Inoculation and Nitrogen Fertilizer on Nodulation and Yield of Selected Tropical Legumes

Many factors affect nodulation of legumes of which, nitrogen fertilizer and method of inoculation play a vital role. Thus, a study evaluated the effects of the above factors on nodulation and yields of two common tropical food legumes, namely Mungbean and Bushbeans which are considered extensive and poor nodulatingo species respectively.
Inoculation increased nodulation of bushbeans and to a lesser extent in mungbeans. This effect was more evident with time. Nodulation was reduced in the presence of nitrogen fertilizer, and the effect was more pronounced in the extensively nodulating species, mungbean. Nitrogen and nodulation increased yields of both species. The results indicate the inability of bushbeans and to a lesser extent mungbean, to meet all nitrogen requirements by nodulation and nitrogen fixation alone. This suggests the need for some fertilizer nitrogen for tropical legumes in addition to inoculation to obtain optimal yields.     

A genotype-by-trait biplot analysis in mungbean (Vigna radiata (L.) Wilczek) genotypes under irrigated and moisture stress conditions

Journal of Crop Science and Biotechnology - To study the impact of terminal moisture stress, thirty-one genotypes of mungbean were screened under irrigated and moisture stress at pod filling stage...     

Effect of Water Stress on the Photosynthesis, Productivity and Water Status of Mung Bean (Vigna radiata L. Wilczek)

The effect of water stress and its subsequent recovery on the photosynthesis, productivity and water status, was examined in three mungbean varieties ( Vigna radiata L. Wilczek) i.e. PS 16, P 105 and Pusa Baisakhi. The variety P 105 was found relatively less susceptible to water stress compared to high susceptibility in Pusa Baisakhi and PS 16. The adverse effect of stress was comparatively higher at the post-flowering and pod development stages. It was observed that variety P 105 had inherently maintained higher water status by retaining higher water potential and water content under water stress condition, thereby effectively reducing the water loss. The higher transpiration rate in this variety regulates the flow of water within the plant. This type of regulation of water flow and maintenance of high water status in P 105 helped to resist the adverse effect of water stress on photosynthesis and productivity. Such adaptation mechanism was not observed in varieties PS 16 and Pusa Baisakhi. The recover) mechanism was, however, operated efficiently in susceptible varieties PS 16 and Pusa Baisakhi particularly for recouping the vegetative growth, but its effect could not be retained for reproductive characters, wherein also variety P 105 due to its efficient partitioning system yielded better than other cultivars.     

Effect of Water Stress on the Yield of Cowpea (Vigna unguiculata L. Walp.) Genotypes in the Delmarva Region of the United States

Drought is an important yield-reducing factor for corn and soya bean which are the two major crops in the Delaware, Maryland and Virginia (Delmarva) region of the United States. Cowpea (Vigna unguiculata L. Walp.) is primarily grown in drier regions of the world where it is one of the most drought-resistant food legumes. Field experiments were conducted in which 10 genetically diverse cowpea genotypes were evaluated for adaptability to the Delmarva area. The cowpea genotypes were grown in rain-out shelters under non-water-stressed and water-stressed conditions. The results showed that under non-water-stressed conditions cowpea genotypes California Blackeye 5, Champion and Mississippi Silver gave higher seed yields, while genotypes White Acre, Six Week Browneye and Texas Cream 8 provided lower seed yields. Genotypes California Blackeye 5 and Champion gave comparatively better seed yields under water-stressed conditions. California Blackeye 5 was the highest seed-yielding genotype under both water-stressed and non-water-stressed conditions. The highest biological yield under non-water-stressed conditions was given by genotypes Two Crop Brown, White Acre and Elite, whereas under the water-stressed condition genotypes Texas Cream 8, California Blackeye 5, and Mississippi Silver gave higher biological yield. Genotypes Quickpick Pinkeye and Elite were identified as early maturing genotypes. The harvest index (HI) varied significantly among genotypes, with Texas Cream 8 having the lowest HI. Cowpea genotypes which gave higher seed yield under water-stressed conditions could play an important role in sustaining crop production in the Delmarva region.     

Effects of Interactions of Moisture Regime and Nutrient Addition on Nodulation and Carbon Partitioning in Two Cultivars of Bean (Phaseolus vulgaris L.)

Major limitations of bean ( Phaseolus vulgaris L.) production in arid and semiarid regions are lack of moisture and low soil fertility. An experiment was conducted to determine the effects of soil moisture and N : P : K (20 : 10 : 10) fertilizer on root and shoot growth of two cultivars of bean: cv. Carioca, an indeterminate Brazilian landrace, and cv. Prince, a determinate cultivar grown in Europe. Carioca appears generally stress-tolerant while Prince is intolerant. Seedlings were grown in pots of non-sterile soil at 30, 60 or 90 % field capacity (FC), and given 0, 0.1 or 1 g (kg soil)^–1 of compound fertilizer. The soil contained a population of effective Rhizobium . Growth of both cultivars was greatest in the high moisture and high nutrient treatments. Root fractions were highest at low nutrient supply; the effect of water was not significant. Leaf fraction decreased as root fraction increased. Numbers of nodules were highest at high and intermediate moisture when no fertilizer was applied. Numbers were lowest at 30 % FC and at the highest fertilizer rate. Masses of nodules and fractions followed the same pattern. Decreasing water regime reduced the relative growth rate (RGR) of Prince, while Carioca maintained high RGR at unfavourable conditions of water and nutrients. Net assimilation rates (NAR) were unaffected by nutrient addition, and reduced by low moisture regime. Water use efficiencies (WUEs) were reduced by water stress but increased by nutrient deficiency. The water utilization for dry matter production was optimal at 60 % FC.     

Yield and Seed Quality of Mungbean as Affected by Irrigation in a Dry Season

A field study was conducted with the objective of determining the effects of soil moisture on seed yield and quality of mungbean ( Vigna radiata L. Wilczek) when grown under rainfed and irrigated conditions in a dry season. Seed quality was determined in terms of germination and production of normal seedlings after controlled deterioration. The presence of adequate soil moisture increased growth and yields of mungbean significantly. The seeds from irrigated plots had a greater weight, owing to heavier cotyledons. Although germination of seeds from the irrigated plots was higher before and after controlled deterioration for 72 h, the number of abnormal seedlings was also greater. Controlled deterioration reduced germination of both categories of seed in the same manner. These factors indicate the low potential of using seeds produced under irrigation in dry seasons as planting material, especially after storage.     

Legume Production and Irrigation Strategies in the Aral Sea Basin: Yield,Yield Components,Water Relations and Crop Development of Common Bean (Phaseolus vulgaris L.) and Mungbean (Vigna radiata (L.) Wilczek)

With world population expected to reach 9.2 billion people by 2050, improved irrigation methods will be needed to increase the productivity of agricultural land and improve food supply worldwide. The objective of this work was to examine the effect of regulated deficit irrigation (RDI) and alternate furrow irrigation (AFI) on the yield and yield components of two legume species (common bean and mungbean) produced as a second crop following winter wheat in Uzbekistan, Central Asia. Water relations and crop development were also examined. The research was conducted during two successive growing seasons in the Fergana valley. Production of mungbean using the severe stress RDI treatment in combination with AFI resulted in the highest yields with the lowest quantity of applied water in 2004. In addition, yields of common bean in the moderate stress treatment were not different from the recommended schedule, although irrigation events were decreased from 4 to 2. AFI did not reduce yields, and it did not interact with RDI to reduce yields further. In general, mungbean yields were higher than those of common bean. The combination of AFI and RDI can allow legume production with reduced water inputs.     

Growth, Yield and Nodule Activity of Phaseolus vulgaris L. as Affected by Soil Moisture

A study evaluated the response of two varieties of beans ( Phaseolus vulgaris L.) to different soil moisture levels during a dry season. The soil moisture regimes maintained throughout the growth period were field capacity, 70–75 %, 50–55 % or 20–25 % available soil moisture.
Plant growth, yield and nodulation were optimal when plants grew at high soil moisture levels. With increasing stress, all measured parameters of both varieties were reduced. However, polebeans, with its vine type of growth was affected to a greater degree than bushbeans. In contrast, nodulation and nodule activity of both variables was affected by moisture stress.
A second experiment evaluated the effects of different soil moisture levels over the growth cycle of bushbeans, which produce greater yields under drier conditions. The highest yields were obtained at higher moisture levels throughout the growth cycle. Moisture stress up to flowering reduced yields to a greater extent than when the plants were subjected to reduced soil moisture after flowering appearance. Some casual mechanisms of the results of the experiments and possible implications for incorporating this popular vegetable legume in rainfed agricultural systems are presented.     

Nitrogen and Carbofuran Effects on the Growth and Yield Performance of Mungbean (Vigna radiata [L.] Wilczek)

Studies were carried out both in the semi-controlled environment and in the field to evaluate the influence of nitrogen and carbofuran in the growth, dry matter partitioning and yield of mungbean. Both nitrogen and carbofuran increased leaf area, leaf N content, NAR, dry matter, most of the yield attributes, and grain yield. Dry matter accumulation during the reproductive phase was significantly influenced by nitrogen and carbofuran, and method of N application. Plants treated with nitrogen fertilizer and carbofuran produced higher amount of dry matter after flowering; but gave low harvest index values compared to control. The results suggest that mungbean yield can be substantially increased through efficient dry matter partitioning employing agronomic manipulations.     

钾肥在豫北潮土区夏玉米上的施用效果初报

通过田间试验研究了河南高产潮土区夏玉米施钾效果及适宜的施用量。结果表明,增施钾肥能明显降低穗位、增加株高﹑穗长、百粒重等增加玉米抗逆性、促进玉米产量构成性状,玉米产量随着施钾量的增加而提高,高钾处理增产幅度变缓,经济效益低。150kg/hm2的施钾量在高肥力潮土上较为适宜。     

钾肥在豫北潮土区夏玉米上的施用效果

通过田间试验研究了河南高产潮土区夏玉米施钾效果及适宜的施用量。结果表明,增施钾肥能明显降低穗位、增加株高﹑穗长、百粒重等增加玉米抗逆性、促进玉米产量构成性状,玉米产量随着施钾量的增加而提高,高钾处理增产幅度变缓,经济效益低。150kg/hm2的施钾量在高肥力潮土上较为适宜。     

Nitrogen Fixation, Growth and Yield of Intercropped Mungbean (yigna radiata L.) and Groundnut (Aracbis bypogaea L.) as Affected by the Genotype

¹⁵N-aided investigations were conducted to ascertain the Nj fixation and the nitrogen (N) contribution by mungbean ( Vigna radiata L.) and groundnut ( Aracbis hypogaea L.) when intercropped with maize ( Zea mays ). The study involved growing seven genotypes of the above legumes with maize in alternate rows in two separate experiments. A sole crop of maize was used as the reference crop to determine N2 fixation by the ¹⁵N methodology. Significant genotypic differences in pod yield and stover N content were observed in intercropped mungbean and groundnut. The percentage N derived from the atmosphere showed a genotypic variation of 31 to 45 % (7 to 10 kg N₂ fixed ha⁻¹O in mungbean and 47 to 69 % (9 to 18 kg N₂ fixed ha⁻¹) in groundnut. Harvest index for N varied from 58 to 77 % in mungbean and 55 to 75 % in groundnut. In groundnut, the uptake of soil N was significantly affected by the genotype. Assuming that the N contribution to the soil by the helow-ground plant parts was negligible, the removal of seeds at maturity resulted in a negative N balance in the soil in all the genotypes of mungbean. In groundnut, some genotypes produced a positive N balance in the soil. Owing to high N₂ fixation capacity and low harvest index for N, groundnut showed a greater N supplementing ability than mungbean.     

Inheritance of evapotranspiration and transpiration efficiencies in diallel F1 hybrids of durum wheat (Triticum turgidum L. var. durum)

Inheritance of water use and transpiration efficiency was studied in diallel F₁ hybrids from six cultivars of T. durum, selected for their different responses to drought stress. Plants were grown in 10 l pots at optimal (control) and low soil moisture levels in the glasshouse. GCA and SCA effects were significant at both soil moisture levels. Results demonstrated that evapotranspiration (ETE) and transpiration efficiency (TE) were under additive and dominant gene control. Interactions of GCA and SCA with moisture levels were also highly significant. GCA effects were the major components of the genetic variance of the biological and generative measures of ETE and TE. Narrow sense heritabilities for both ETE and TE based on grain yield were higher at the soil stress moisture level. Heritability estimates of ETE and TE based on the total biological yield, however, declined under the lower soil moisture level. Measures of ETE and TE showed significantly high and positive genotypic and phenotypic correlations among them as well as with grain yield and harvest index. In most cases, genotypic correlations were higher than phenotypic correlations. The results suggest that selection for high ETE and TE in terms of grain yield should be undertaken under both stress and optimal conditions. Selection in early segregating generations may lead to effective identification of desirable recombinants. This revised version was published online in August 2006 with corrections to the Cover Date.