Root Characteristics of Black Beans. II. Morphological Differences Among Genotypes1

Basal root whorl number: a modulator of phosphorus acquisition in common bean (Phaseolus vulgaris).

Core Ideas Black bean cultivars were extremely susceptible to high salinity stress. Seed elicitation improved salinity stress resilience. Chitosan oligosaccharide and marine peptide were used for seed elicitation. Adaptive response to salinity stress varied among black bean cultivars. Seed elicitation induced phenolic‐linked antioxidant enzyme responses. The adaptive responses of plants to abiotic stress include stimulation of secondary metabolites and endogenous antioxidant enzymes through up‐regulation of the pentose phosphate pathway (PPP). Therefore improving abiotic stress resilience in food crops through upregulation of critical redox‐linked anabolic PPP and enhancement of phenolic‐linked antioxidant enzyme responses has merit. This study evaluated the effects of seed elicitor treatments (chitosan oligosaccharide [COS] Kong Poong Bio, Jeju, Korea, and marine hydrolysate [GroPro], Icelandic Bioenhancer, Harrison, NY) to improve salinity stress resilience through up‐regulation of PPP in black bean (Phaseolus vulgaris L.) cultivars. Eclipse and Zenith cultivars were subjected to elicitor treatments (1%) and then 1 wk after germination were transplanted into three soil salinity treatments (no salt, 2–3, and 5–6 dS m−1) in greenhouse. Elicitation resulted in enhanced survival at medium salt stress (2–3 dS m−1), however none survived more than 55 to 60 d post germination under high salt stress (5–6 dS m−1). Stimulation of phenolic biosynthesis through up‐regulation of PPP was confirmed in Eclipse, while Zenith exhibited higher reliance by stimulation of endogenous antioxidant enzyme responses to counter salinity stress. GroPro induced elicitation improved total soluble phenolic content (60 d) and higher glucose‐6‐phosphate dehydrogenase (G6PDH) activity (45 d) in Eclipse. In Zenith, GroPro stimulated antioxidant enzyme responses (superoxide dismutase [SOD] and guaiacol peroxidase [GPX]) during later growth stages, while COS elicitation improved antioxidant response in early stages. Therefore seed elicitation can be a selective strategy to improve salinity stress resilience in black bean.

The Phaseolus vulgaris I locus-Bean common mosaic virus (BCMV; Potyviridae) pathosystem is of critical importance to bean geneticists, breeders and pathologists because of the worldwide distribution of both the virus and germplasm containing this resistance gene. In order to learn more about the molecular responses characteristic of this resistance gene, a cDNA-AFLP screen was conducted on homozygous NILs of P. vulgaris variety 'Black Turtle Soup' (BT), containing either the I locus allele for resistance (BT(II)) or susceptibility (BT(ii)) to BCMV. Eight conditions were compared in a factorial analysis: BT(II) versus BT(ii); mock inoculated versus BCMV inoculated; 26 versus 34 degrees C. Transcripts induced in response to viral infection and that were further responsive to temperature, genotype or both were isolated and cloned. Sequence analysis of the resultant clones revealed several classes of putative genes, including transcription-related and signal transduction-related genes. Review of disease resistance literature suggests further avenues of research involving the candidates isolated in this screen.

The soil in the production of clonal seedlings of black pepper (Piper nigrum L.) contributes to fusarium and nematodes infestation in commercial crops, and thus the usage of alternative substrates might be a preventive control measure against these pathogens. The aim of this study was to investigate the rhizogenic behavior of the cultivars Bragantina, Iaçará and Guajarina of black pepper in different substrates. The experimental design was in randomized blocks in a 3x4 factorial design (cultivars: Bragantina, Iaçará and Guajarina x substrates: soil + organic compound (18%), vermiculite, carbonized rice hulls and commercial substrate), with four replications of 16 cuttings each. The evaluated characteristics were: survival (%); rooting (basal or nodal) (%); nodal rooting (%); basal rooting (%); number of nodal roots; number of basal roots; total number of roots; length of the largest nodal root (cm); basal root length (cm); nodal root volume (cm3); basal root volume (cm3); Total root volume (cm3); nodal root dry mass (mg); basal root dry mass (mg) and the total root dry mass (mg). There are differences within black pepper cultivars as to the characteristics related to the root system. The vermiculite substrate was the most suitable, and carbonized rice hull is not recommended for the adventitious rooting of cuttings of cultivars Bragantina, Iaçará and Guajarina.

The activity of soil pathogens, competition for assimilates, and the changing availability of below-ground resources make root systems subject to a continuous and dynamic process of formation and loss of both fine and coarse roots. As hypocotyl borne roots appear later than other root classes, they may serve to functionally replace basal and primary roots lost to biotic and abiotic stress. Using common bean (Phaseolus vulgaris L.), we conducted experiments in solution and solid media culture with treatments involving the removal of part of the root system (basal, hypocotyl borne or primary roots), phosphorus availability, and depth of seeding to test the hypothesis that there are compensation mechanisms among basal, hypocotyl borne and primary roots to cope with the loss of part of the root system. The root system was highly plastic in response to root excision, which resulted in the maintenance of below-ground biomass accumulation. In most cases, this compensation among root classes was enough to maintain plant performance in both phosphorus sufficient and phosphorus stressed plants. Removal of a specific root class induced an increase in the growth of the remaining root classes. All root classes, but especially the primary root, contributed to the compensation mechanism in some way. Primary roots represented around 10% of the root system in control plants and this proportion increased dramatically (up to 50%) when other root classes were removed. In contrast, negligible compensatory re-growth was observed following removal of the primary root. Greater planting depth increased the production of hypocotyl borne roots at the expense of basal roots. The proportion of hypocotyl borne roots increased from 25% of the whole root system when seeds were placed at a depth of 2 cm to 30% when they were placed at 5 cm and to 38% when placed at 8 cm, with corresponding decreases in the proportion represented by basal roots. The common feature of our observations is the innate ability of the root system for its own regeneration. Total root biomass maintained strict allometric relationships with total shoot biomass in all treatments. Re-stabilization of root to shoot balance after partial root loss is governed by overall plant size following allometric relationships similar to undisturbed plants. However, the pattern of this root regeneration was not uniform since the way the three root classes compensated each other after the removal of any one of them varied among the different growth media and phosphorus supply conditions. The resulting changes in root architecture could have functional significance for soil resource acquisition.

Arbuscular mycorrhizas enhance nutrient uptake in different wheat genotypes at high salinity levels under field and greenhouse conditions

A 2 year trial was conducted with 15 cucumber ( Cucumis sativus L.) varieties from diverse origins in the greenhouse conditions (southern Iran) to study genetic variation and to identify genetically distant parents to be involved in a hybrid seed production as well as to identify the most effective components of grain yield. However, the potential of identifying genetically distant parents depends on genetic diversity of population. The varieties were cultivated in a randomized complete block design (RCBD) with 3 replications for 2 years (2004 - 2006 seasons). Characters such as, yield and number of fruits in surface unit (m 2 ), yield in cold season, diameter and length of stem, length and diameter of fruit were evaluated analyzed for 2 years. Compound variance analysis showed that there were significant differences ( Cucumis sativus L.) varieties from diverse origins in the greenhouse conditions (southern Iran) to study genetic variation and to identify genetically distant parents to be involved in a hybrid seed production as well as to identify the most effective components of grain yield. However, the potential of identifying genetically distant parents depends on genetic diversity of population. The varieties were cultivated in a randomized complete block design (RCBD) with 3 replications for 2 years (2004 - 2006 seasons). Characters such as, yield and number of fruits in surface unit (m 2 ), yield in cold season, diameter and length of stem, length and diameter of fruit were evaluated analyzed for 2 years. Compound variance analysis showed that there were significant differences ( Cucumis sativus L.) varieties from diverse origins in the greenhouse conditions (southern Iran) to study genetic variation and to identify genetically distant parents to be involved in a hybrid seed production as well as to identify the most effective components of grain yield. However, the potential of identifying genetically distant parents depends on genetic diversity of population. The varieties were cultivated in a randomized complete block design (RCBD) with 3 replications for 2 years (2004 - 2006 seasons). Characters such as, yield and number of fruits in surface unit (m 2 ), yield in cold season, diameter and length of stem, length and diameter of fruit were evaluated analyzed for 2 years. Compound variance analysis showed that there were significant differences (
= 0.01) in yield between varieties at 2 years and the highest yield (23.81 kg/m 2 ) was obtained for E3215516 variety. Correlation analysis of varietal means showed that the highest correlation (0.932) was observed between number of fruits (NOF) and yield, and the least (0.01) between diameter of stem (DOS) and length of fruit (LOF). Based on factor analysis, 3 components were identified, explaining 77.5% of observed variation. Factor 1 (yield factor) accounting for about 45% of the variation, was strongly associated with yield, yield in cold season and number of fruits. Factor 2 (source factor) accounting for about 18% of the variation, consisted of stem related components including diameter of stem (DOS) and length of stem (LOS). Factor 3 (sink factor) accounting for about 15% of the total variation, associated with length and diameter of fruit (LOF and DOF). Using cluster analysis, the lines were classified into 2 distinct classes A and B. Class B contained lines from different origins.

Tomato ( Solanum lycopersicum L.) is one of the most extensively cultivated horticultural crops in the world. Factors such as yield, size, taste, and lycopene content are important criteria that may impact the selection of tomato cultivars for different production systems. The aim of the current study was to evaluate different slicer and cherry tomato cultivars for production under greenhouse and open field conditions. Three cultivars of slicer (BHN 964, Trust, and Geronimo) and cherry (BHN 268, Favorita, and Sakura) tomatoes were tested using randomized complete block design in 2019 and 2020. Results showed that the performance of tested cultivars differed under greenhouse verses open field conditions. Among cherry tomato cultivars in 2020, BHN 268 and Sakura produced significantly greater yield under open field conditions, while under greenhouse conditions yield of BHN 268 was the lowest. Similarly, cherry tomato fruit size from ‘BHN 268’ and ‘Sakura’ was also significantly greater than ‘Favorita’ under field conditions, whereas under greenhouse conditions, the fruit size of ‘Sakura’ was significantly greater than both ‘BHN 268’ and ‘Favorita’. Among slicer tomato cultivars, BHN 964 produced significantly greater yield and had a greater average fruit size than the other two cultivars under greenhouse conditions in 2020 while, Geronimo produced significantly similar or larger yield and had a similar average fruit size compared with BHN 964 under open field conditions. Tomatoes produced under open field conditions were rated significantly greater for taste compared with those produced under greenhouse conditions. Lycopene content in both slicer and cherry tomato cultivars was influenced by the interaction of production type, cultivars, and harvest time. Therefore, it can be concluded that BHN 964 and Geronimo were the highest in lycopene among slicer tomato cultivars for greenhouse and open field production, respectively. Among cherry tomato cultivars, BHN 268 was the highest in lycopene for open field production and Sakura for greenhouse production. Additionally, open field–produced tomatoes taste better than greenhouse-produced tomatoes, but lycopene content may be constrained for mid- and late-season fruits due to high temperature conditions under open field conditions.

Efficacy of compost, bioagents and some commercial biocides individually or in combination for controlling tomato sclerotinia rot caused by Sclerotinia sclerotiorum (Lib.) de Bary under greenhouse and field conditions were studied. Results indicated that Trichoderma album and Bacillus subtilis were the most effective bioagents in inhibiting mycelial growth of S. sclerotiorum in vitro. All treatments significantly reduced disease incidence and severity of tomato white rot disease compared with untreated control. However, T. album and Pseudomonas fluorescens combined with compost reduced the disease incidence and disease severity from 100 and 77.40 in control to 11.1 & 1.5% and 11.1 & 2.5%, respectively, under greenhouse conditions. The integrated T. album, P. fluorescens and Bio-Zeid with compost recorded the highest increase of fresh weight and dry weight of shoots and roots compared with individual treatments and control. Under field conditions, adding compost to the soil pre-transplanting decreased the percentage of infection and increased yield of tomato plants compared with other treatments with compost. In this respect, the integration between T. album + B. subtilis + Ps. fluorescens and compost was the most effective treatment for reduced the disease incidence and disease severity. As well as, this treatment increased the fruit weight per plant. On the side, all treatments increased the phenols and flavonoids content in tomato plants. The highest increase in the total phenols and flavonoids contents were recorded with T. album, P. fluorescens and Bio-Zeid combined with compost. Also, all treatments increased peroxidase (PO), polyphenoloxidase (PPO), chitinase and β-1, 3- glucanase activities in treated tomato plants. It could be concluded, the combination between compost, bioagents and some commercial biocides might be useful as an useful tool for controlling tomato sclerotinia disease under greenhouses and field conditions.

This study was conducted to evaluate the terminal residue of a new fungicide, KNF 1002, in cucumber and pepper under greenhouse and field conditions. When a microemulsion formulation (20%) of KNF 1002 was applied once or twice during days before harvest, its terminal residue in cucumber ranged under greenhouse condition. In pepper, its figure recorded and under greenhouse and field conditions, respectively. Much higher level of terminal residues was observed in leaves than those in fruits in pepper, showing and under greenhouse and field conditions, respectively. Cultivation condition affected evidently the residue level in pepper harvests. Residual pattern of KNF 1002 seemed to be comparable to strobilurin fungicides currently used.

Fusarium oxysporum f. sp. lentis is the most important pathogen of lentil plants, and most areas under lentil cultivation are reported to have a fusarium wilt disease background. The plants are infected in the seedling stage and later stages of their development. Fusarium wilt disease, which has appeared at high incidence rates during recent years, has caused sharp drops in the yield, especially in Moghan, in the northwest of Iran. Forty-five isolates of the pathogen were collected from different regions of the country with two isolates from ICARDA in the summer of 2008 and identified using Nelson’s key. The pathogenicity of the collected isolates was studied on a sensitive line (ILL 4605) under greenhouse conditions and significant differences in pathogenicity were found among them. The most pathogenic isolates from three provinces, East Azerbaijan (EA 30), Ardebil (Ar 3) and Khorasan (Kh 45), were selected and used in screening of 55 developed lines under greenhouse and field conditions. In the greenhouse, test plants were inoculated by immersing root tips in spore suspension and sowing seeds in pre-infested pot soil. Field tests were carried out in a naturally highly infested farm. At all stages, the plant response to the disease was based on the percentage of dead plants. Cluster analyses of the greenhouse and field data led to the selection of three lines (81S15, FLIP2007-42 L and FLIP2009-18 L) that were resistant under greenhouse and field conditions.

Developmental patterns and abscission of flowers and pods were studied in greenhouse and field experiments with three cultivars of dry beans (Phaseolus vulgaris L.). The pattern of flower production, pod retention, number of flowers produced, and percentage of reproductive structures abscised varied with cultivar. The pattern of flower production varied from a concentrated skewed pattern for cultivar ‘Seafarer’ to a longer and more normally distributed pattern for cultivar ‘Black Turtle Soup’. In general, the first‐formed flowers had the highest probability of setting pods and producing mature seed.

Cowpea bacterial blight, caused by Xanthomonas axonopodis pv. vignicola (Xav), can severely reduce the yields of cowpea in tropical regions. Despite its destructiveness, research on the epidemiology of bacterial blight is scarce in Brazil. The objectives of this study were to quantify the effect of the Xav inoculum concentration and of the duration of leaf wetness periods on disease severity, in addition to assessing bacterial transmissibility by seed and to identify indicator plants that might be used for simple diagnostic tests. In experiments conducted in greenhouse and field conditions, cowpea plants were inoculated with 105, 106 and 107 CFU (colony forming units) of Xav/mL, and seeds harvested from field plots were used to determine the transmissibility of the bacteria. Under greenhouse conditions, plants were subjected to leaf wetness duration periods of 0, 4, 8, 12, 16, 20 and 24 h after inoculation. In another experiment, soybean, common bean and wild poinsettia were inoculated with Xav. It was observed that plants inoculated with a concentration of 107 UFC/mL and subjected to 12 h of leaf wetness had higher disease severity. There was transmission of Xav to the seeds in all inoculum concentrations used. Hypersensitivity reaction was observed in wild poinsettia less than 24 h after inoculation.

Accumulation of Ca, Mg and K, the principal cations in dry bean (Phaseolus vulgaris L) seed, was studied under field and greenhouse conditions. ‘Cran-09’, a cranberry bean and ‘Norstar’, a navy bean, were grown to maturity under greenhouse conditions. ‘Cran-09’ had a seed weight of 605 mg, a seed Ca concentration of 1·2 g kg-1 and a Ca harvest index of 0·032. The corresponding three parameters in ‘Norstar’ were a seed weight of 161 mg, a seed Ca concentration of 2·2 g kg-1 and a Ca harvest index of 0·064. The difference in seed Ca concentration was not due to increased absorption of Ca by ‘Norstar’, but rather was due to a larger proportion of Ca in plant tops being diverted to the seed component. The larger seed Ca concentration in ‘Norstar’ was compensated to some extent by a smaller seed K concentration. In contrast to Ca, cultivar had relatively little effect on harvest indices for Mg, K, N and P. The average seed Ca concentration in six navy bean cultivars grown under field conditions was 90% more than that of three kidney and three cranberry bean cultivars. © 1997 SCI.

The witches' broom (Crinipellis perniciosa) is the most important disease of cacao in Brazil. The main method of disease control is the use of resistant cultivars, however due to the narrow genetic basis found in commercial cacao growing areas, the resistance is frequently broken. The objectives of this work were: to select new sources of resistance to C. perniciosa among cacao accessions originally collected in the Brazilian Amazon (CAB series); to identify by genetic mapping, quantitative trait loci (QTLs) associated with resistance in selected genotypes; and to evaluate the genetic relationship between the selected accessions and clones selected by cacao growers from Southern Bahia with traditional resistance sources against C. perniciosa. Based on the proportion of witches' broom infection, the levels of resistance to C. perniciosa were estimated in 44 cacao families under greenhouse and field conditions. Under greenhouse conditions, the average proportion of infection was compared based on Wald test, and under field conditions using an analysis of repeated measures and contrast. Among the families evaluated under greenhouse and field conditions, the ones with least incidence of witches' broom symptoms derived from 'CAB 0169', 'CAB 0208', 'CAB 0214', 'CAB 0270', 'CAB 0371', 'CAB 0388', 'CAB 0392' and 'CAB 0410'. Two linkage maps were developed for populations derived from crosses between contrasting accessions selected as the most resistant to C. perniciosa ('CAB 0208' and 'CAB 0214') and a susceptible accession 'ICS 39'. The linkage maps were developed using 65 microsatellite loci, applying the software JoinMap 3.0 . The identification and localization of QTLs associated with resistance to C. perniciosa were performed using MAPQTL TM 4.0. For the family derived from 'ICS 39 x CAB 0208', 11 linkage groups were formed, with total coverage of 541 cM and 14 cM average distance between markers. The linkage map from 'ICS 39 x CAB 0214' presented a total coverage of 501 cM in 10 linkage groups formed with an average distance between markers of 11.4 cM. Three QTLs associadted with resistance to C. perniciosa were detected, with one at linkage group VIII of 'ICS 39 x CAB 0208', and two for the 'ICS 39 x CAB 0214' family, with one located at linkage group IV and another at group IX. The genetic relationship between these two CAB accessions and 81 genotypes used as source of resistance to C. perniciosa were determined using genetic dissimilarity and co-ancestry based on allele frequencies of 20 microsatellite loci. The dissimilarity analyses among the accessions generated two distinct groups. 'CAB 0208' and 'CAB 0214' did not belong to any of the two groups. The co-ancestry between the two accesions were high, close to full-sib, but without any relationship with any of the other genotypes. The clones selected by growers derived mostly from 'Scavina 6', a commonly used source of resistance to C. perniciosa.