Impact of simulated Helicoverpa zea (Lepidoptera: Noctuidae) feeding in soybeans with determinate and indeterminate growth habits

Helicoverpa zea (Boddie) is a polyphagous pest that can cause serious damage to crops, including soybeans (Glycine max L.). In soybeans with both determinate and indeterminate growth habits, H. zea larvae are more commonly found on leaves compared to blooms, stems, and pods. Past research demonstrated that H. zea adults tend to oviposit near the upper part of the plant canopy in soybeans with a determinate growth habit. However, ovipositional selection on soybeans with an indeterminate growth habit is unknown. We hypothesized that H. zea would oviposit more uniformly throughout the canopy on indeterminate soybean growth habits due to more diffuse reproductive tissue. We planted field and greenhouse experiments with varieties sharing a similar relative maturity (2 maturity group [MG] 5.2 varieties and 2 MG 5.4/5.5 varieties) but with different growth habits. To test oviposition selection, adult H. zea females were allowed to oviposit under field and caged conditions. We counted the number of H. zea eggs and neonates on each plant tissue type from each of 3 equal parts in the plant canopy: upper, middle, and lower. In both experiments, eggs and neonates were most common on leaves at the top of the plant regardless of soybean growth habit. Consequently, ovipositional selection is likely independent of reproductive tissue availability, and patterns of oviposition through the canopy are similar in growth habits. An improved understanding of H. zea ecology in soybeans relative to indeterminate growth habits may improve recommendations for managing this significant pest of soybean.

In order to evaluate the ideal time of herbicide applications to desiccate soybean cultivars with determinate and indeterminate growth habits in preharvest, an experiment was carried out at the University of Ponta Grossa (PR), during 2002–2003. The experimental design used was a randomized blocks arranged in a factorial scheme 4×,5 (herbicides and time of application), with three replications, using four soybean cultivars: Spring, V-Max, BR-16, and BRS-133. The herbicides glufosinate, diquat, and paraquat were used at the rate of 400 g ha-1, when soybean was at stage of R6.0, R6.5, R7.0, R7.5, and R8.0. The assessments included yield, as well as yield components, considering each cultivar separately. The results show that desiccation should be done on cultivars with determinate growth habit at stages between R7.0 and R7.5, independent of herbicide used. For indeterminate growth habit cultivars, desiccation should be done later, because those pods formed after R6.5 stage are important to define yield; although herbicides have different mode of action, yield results were similar. In cultivars, desiccation should start when all pods in the middle of plants become yellow and grains are not held by fibers.

Plant height, determinate growth habit, and brachytic stem are 3 major plant-type traits of soybean. In this report, a population of 151 recombinant inbred lines (RILs) derived from the cross of Bogao (high stature, indeterminate growth habit, and normal stem) and Nannong 94-156 (short stature, determinate growth habit, and brachytic stem) was used to map genes and quantitative trait loci (QTLs) for 3 plant-type traits and to reveal the effects of brachytic stem on yield-related traits including seed yield, apparent biological yield, apparent harvest index, plant height, and days to maturity. The results indicated that brachytic stem (sb) and determinate growth habit (dt1) were mapped on linkage groups B2 and L, respectively. Two major QTLs related to plant height were detected and mapped on linkage group L near dt1, and 0.6 cM above the Sb locus on linkage group B2 across 2 years. These 2 QTLs explained 15.1% and 52.7% of the phenotypic variation, and decreased plant height by 9.2 and 17.6 cm, respectively. It was found that only one QTL was detected and mapped on linkage group L near dt1 across 2 years. Lines with brachytic stem had shorter plant height, lower biomass, yield, and harvest index, and essentially no differences in days to maturity when compared with normal stem lines.

Comparison of common buckwheat varieties with determinate vs. indeterminate growth habit reveals no differences in leaf photosynthesis rate at stage before flowering. However, at stage of seed filling the difference was significant. Maximal difference was 20 days after early flowering, i.e in period of most intensive seed formation. These results show that determinate varieties have higher sink strength providing by developing seeds. It is correlated with higher yield ability of such varieties. Probably, growth limitation resulting from det-mutation leads to some shifts in system of sink priorities of buckwheat plant and allows initiate the development of additional seeds. One more possible cause of alteration of the physiological parameters in determinate varieties is some optimization of plant structure: in terms of physiology the determinate buckwheat is a plant which is more similar to cereals than indeterminate buckwheat. However, underlying physiological changes accompanying the transition from indeterminate toward determinate growth in buckwheat remain almost unknown. Assumption about strong effect of det-mutation per se on photosynthesis rate was not supported in our work. Alternative assumption about accumulation of additional genes enhancing the sink ability suggests opportunities for additional progress in the selection work using tools evaluating photosynthesis intensity at stage of grain filling.

Growth habits are among the essential adaptive traits acted upon by evolution during plant speciation. They have brought remarkable changes in the morphology and physiology of plants. Inflorescence architecture varies greatly between wild relatives and cultivars of pigeon pea. The present study isolated the CcTFL1 (Terminal Flowering Locus 1) locus using six varieties showing determinate (DT) and indeterminate (IDT) growth habits. Multiple alignments of CcTFL1 sequences revealed the presence of InDel, which describes a 10 bp deletion in DT varieties. At the same time, IDT varieties showed no deletion. InDel altered the translation start point in DT varieties, resulting in the shortening of exon 1. This InDel was validated in ten varieties of cultivated species and three wild relatives differing in growth habits. The predicted protein structure showed the absence of 27 amino acids in DT varieties, which was reflected in mutant CcTFL1 by the absence of two α-helices, a connecting loop, and shortened β-sheet. By subsequent motif analysis, it was found that the wild-type protein had a phosphorylation site for protein kinase C, but the mutant protein did not. In silico analysis revealed that the InDel-driven deletion of amino acids spans, containing a phosphorylation site for kinase protein, may have resulted in the non-functionality of the CcTFL1 protein, rendering the determinate growth habit. This characterization of the CcTFL1 locus could be used to modulate growth habits through genome editing.

The inheritance of five characteristics namely branching behaviour, clustering pattern, growth habit, leaf size and hairiness was studied in clusterbean. All the traits were controlled by single pairs of genes except branching behaviour which exhibited digenic inheritance. Complementary gene effects were involved in the expression of branching in the F1 and F2 generations; the F2 showing a ratio of 9:7 for branched to unbranched genotypes in the cross FS 277 × NC 70 where both the parents were single shooted. The alleles governing branching, discontinuous clustering, indeterminate growth habit, small leaf size and hairiness were dominant over the alleles controlling non-branching, continuous clustering, determinate growth habit, broad leaf and glabrous leaf and stem.

When soybean [Glycine max (L.) Merr.) is double‐cropped with small grains, as is often done in the southeastern USA, it yields less than full‐season soybean. Incorporation of indeterminate growth habit into adapted germplasm has been suggested as a means of reducing the yield loss associated with delayed planting of determinate soybean (the predominant plant type grown in the Southeast). Little is known about management of indeterminate soybean in late‐planted systems. Our objective was to compare response of determinate and indeterminate growth habit to row spacings and planting dates within a late‐planted, narrow‐row cropping system. Determinate ‘Braxton’ [maturity group (MG) VII] and ‘Kirby’ and indeterminate experimental genotypes G82‐8468 and G84‐9006 (MG VIII) were compared in 0.60‐ and 0.30‐m row spacings, and in June and July plantings for 4 yr in Alabama (32°30' N lat). Determinates yielded more than indeterminates, but indeterminates had less yield loss caused by delayed planting. Indeterminate plant height was reduced more by later planting, but was greater than determinates in both plantings. Seed‐filling period was reduced in the later planting in both determinate and indeterminate genotypes. Indeterminates had more mainstem pods and nodes per plant than determinates. Plants in 0.30‐m rows had fewer days to canopy closure, mainstem nodes, number of branches, pods per branch, and pods per plant than plants in 0.60‐m rows, but yields were not different. We concluded that row spacings <0.60 m between rows provide no advantage for late‐planted soybean, and neither growth habit has any advantage for yield in late‐planted, narrow‐row cropping systems.

Key messageWe report growth habit profiling following SEM, genetic mapping and QTL analysis. HighlightedCcTFL1, a candidate for determinacy in pigeonpea, since an Indel marker derived from this gene co-segregated withDt1locus.Pigeonpea (Cajanus cajan) is one of the most important legume crops grown in arid and semi-arid regions of the world. It is characterized with few unique features compared with other legume species, such as Lotus, Medicago, and Glycine. One of them is growth habit, an important agronomic trait. In the present study, identification of mutations affecting growth habit accompanied by a precise analysis of phenotype has been done which will shed more light upon developmental regulation in pigeonpea. A genetic study was conducted to examine the inheritance of growth habit and a genotyping by sequencing (GBS)-based genetic map constructed using F2 mapping population derived from crossing parents ICP 5529 and ICP 11605. Inheritance studies clearly demonstrated the dominance of indeterminate (IDT) growth habit over determinate (DT) growth habit in F2 and F2:3 progenies. A total of 787 SNP markers were mapped in the genetic map of 1454 cM map length. Growth habit locus (Dt1) was mapped on the CcLG03 contributing more than 61% of total phenotypic variations. Subsequently, QTL analysis highlighted one gene, CcTFL1, as a candidate for determinacy in pigeonpea, since an Indel marker derived from this gene co-segregated with the Dt1 locus. Ability of this Indel-derived marker to differentiate DT/IDT lines was also validated on 262 pigeonpea lines. This study clearly demonstrated that CcTFL1 is a candidate gene for growth habit in pigeonpea and a user-friendly marker was developed in the present study which will allow low-cost genotyping without need of automation.

The value of intra- and interracial populations in common bean (Phaseolus vulgaris L.) needs to be determined in order to create useful genetic variation for maximizing gains from selection, broadening the genetic base of commercial cultivars, and making efficient use of available resources. Five large-seeded parents of race Nueva Granada (N), two small-seeded race Mesoamerica (M), and one medium-seeded race Durango (D) were hybridized to produce one intraracial (N x N) and three interracial (two N x M and one N x D) populations. Seventy-nine F2-derived F6 lines randomly taken from each population along with their parents were evaluated for agronomic traits and markers at Palmira and Popayán, Colombia, in 1990 and 1991. Variation for agronomic traits and for morphological, protein, and isozyme markers was larger in interracial populations than in the intraracial population. Mean seed yield of all lines as well as yield of the highest yielding line from two interracial populations were significantly higher than that of the intraracial population. The highest (≥ 0.80±0.15) heritability was recorded for 100-seed weight. Values for seed yield varied from 0.19±0.17 to 0.50±0.16. Gains from selection (at 20% selection pressure) for seed yield ranged from 3.9% to 11.4%. Seed yield was positively associated with biomass yield, pods/m(2), and days to maturity, but harvest index showed negative correlations with these traits and a positive value with 100-seed weight. Polymorphism was recorded for phaseolin, lectins, protein Group-1 and protein Group-2 fractions, and six isozyme loci. Lines with indeterminate growth habit had significantly (P < 0.01) higher seed yield than lines with determinate growth habit in a Redkloud x MAM 4 population. Also, 23 other associations of markers with agronomic traits other than seed yield were recorded. Of these associations, lines with T phaseolin, the Diap1 (2) allele, and lilac flower color tended to possess greater seed weight.

Changes in the proportion of the total biomass harvested have made an important contribution to the increase in yield in several grain crops. Field experiments were conducted for several years on Typic Argiudoll and Typic Paleudalf soils to investigate the effect of cultivars, growth habit, and environmental conditions on the partitioning of assimilate between vegetative and reproductive plant parts in soybean [Glycine max(L.) Merr.] during flowering and fruit set. The experiments included the following variables; cultivars from maturity group II to V, including both indeterminate and determinate growth habits, optimum and delayed plantings, and moisture stress. Data were collected from growth stage R1 to R6 on vegetative growth characteristics (nodes on main stem, total nodes, and plant height), pod development, and weight of vegetative and reproductive plant parts. Partitioning coefficients were calculated by dividing fruit weight by the total aboveground biomass. The nodes on the main stem and on the branches reached a maximum at R5 in all cases. Determinate cultivars produced fewer nodes on the main stem between R1 and R5; however, they produced more branch nodes and the total node production was greater than the indeterminate cultivars. The number of pods containing developing seed increased until approximately R6, suggesting that the production of new vegetative sinks (node production) in soybean stopped before the total fruit load was established. The partitioning coefficients increased rapidly from &lt; 5% at growth stage R3 to ≥ 30% at R6. The partitioning coefficient at any growth stage varied only slightly across the variables included in the experiments. This suggests that variation in fruit and seed number may be more closely related to variations in crop growth rate than to variations in the allocation of assimilate between vegetative and reproductive plant parts.

This investigation has been carried out to group soybean varieties into several types by yield components and to characteraize these types as to plant type and growth habit. Out of one hundred three varieties, collected from western part of Japan and examined, data of 84 varieties which yielding more than 200g/m2 were analyzed. And the following informations were obtained. 1) Soybean varieties were grouped into five types (Grain-Number type, Semi Grain-Number type, Medium type, Semi Grain-Size type, Grain-Size type) on the basis of Seed Number·100-Seed Weight ratio. Grain-Number (GN) type has the largest Seed Number·100-Seed Weight ratio and Grain-Size (GS) type has the smallest one. 2) GN type included more blanched type and blanch-spreaded type, based on the plant type classification suggested by WATANABE et al.14) in 1975. 3) GN type had longer vegetative period, whereas GS type had longer reproductive period. 4) On growth habits, GN type had more vigorous both vegetative and reproductive growth than GS type, and GN type had more vigourous growth of branches. 5) GN type was supposed to be advantageous under favourable conditions and GS type vice versa. 6) Recent soybean breeding in Japan seems to give too much weight to seed size. It might be necessary to consider balance of seed number and seed size.

Plant height is an important architectural trait that affects crop growth, yield, and stress resistance. Tremendous efforts have been dedicated to revealing the genetic basis or regulatory mechanism; however, the underlying molecular mechanism remains largely unknown primarily due to the lack of controlling genes. In this study, we conducted a single-nucleotide resolution genome-wide association study (GWAS) of plant height using a diverse soybean panel collected worldwide with 6.7million genome-wide variants (SNPs and Indels). The GWAS of plant height identified three QTLs on chromosomes 10, 18, and 19, of which the one on chromosome 19 precisely co-localized with Dt1, known as a major stem growth habit-controlling gene. Other loci without reported genes for plant height were regarded to be new. A close investigation within QTL intervals proposed nine genes that were likely involved in the regulation of plant height according to the expression specificity in developing shoot tip meristems. VRN1-2 underlies the significant QTL on chromosome 10 was prioritized as the most promising candidate gene. VRN1-2 shows higher expression in Williams 82 with indeterminate growth habit than Dongnong50 with semi-determinate growth habit across vegetative (V2, V3) and reproductive (R1) growth stages. VRN1-2 carries non-synonymous variants in the coding region that were significantly associated with plant height variation. The GT allele conferring short plant height was likely subjected to artificial selection during domestication. These results provide a source of new loci and genes for further elaborating the regulatory mechanism of plant height and the key variants would facilitate soybean molecular breeding.

String beans a vegetable of high nutritional quality and there is a tendency in Mexico to increase its consumption. It was therefore the objective of this research to identify varieties of string beans adapted to the Valley of Mexico with different growth habits based on their productivity and quality on two planting dates. An experiment with 36 varieties of beans (31 had a determined growth habit while 5 had an undetermined) was established on May 21 and June 15, 2001 in Texcoco, in the state of Mexico. The flowering dates, date of cutting, physiological maturity, total production, and length of the string beans was noted, as well as the seed yield. The protein and crude fiber content of the string beans were evaluated on the first date of planting (PFS). Significant differences (P£0.01), were found in all the quantified variables. The drop in temperature, the photoperiod and the hydro availability reduced the number of string bean cuts of eight of the PFS and of five of the second. The varieties with undetermined habits had a higher total yield of string beans and seeds. Ejotero 50, OR 900 and US No. 3 varieties had an average higher total yield of string beans in the PFS and may be used in early plantings. US No. 3, E10-1, F2 and E10-2 varieties were outstanding on the second date and may be used in late plantings. During the last two planting dates, Bayo Alteño showed a resistance to diseases and a high string bean and seed yield so it can therefore be planted for a double purpose (string beans and grain) and as a progenitor in genetic improvement of string beans. The obtained yield and quality show that it is possible to produce string beans in the Valley of Mexico.

Mutations are the key drivers for evolution and diversification in plants. In varietal selection, sources for variation are always sought as starting breeding materials. Thus, in the absence of desired natural variations in breeding populations, targeted or random mutagenesis is applied to induce variations. Cultivated potato (Solanum tuberosum L.) is autotetraploid crop species with a narrow and highly heterozygous genetic base, and the complexity of its genome makes its genetic studies more difficult. In the current study, induced mutagenesis was performed in diploid potato using ethyl methane sulfonate (EMS) to enlarge the genetic variability for its use as pre-breeding materials in both polyploid and diploid potato breeding. As starting materials, true potato seeds were treated with 1.2% EMS for 4–6 h along with untreated seeds as controls. A large variation in terms of germination rate, plant, flower, and tuber phenotype was observed in EMS-treated plants compared with their untreated counterparts. In particular, abnormal phenotypes including twisted stem, partial and (or) completely chlorotic leaves and stems, variations in stem colour and weak-stemmed plants with lateral growth habit as well as plants with determinate growth habit were observed along with normal plant characteristics. Moreover, variations in flower colour and tuber colour, shape, and size, as well as yield potential, were observed in EMS-treated lines. The reported phenotypic characterization of EMS mutagenized diploid potato collection is to our knowledge the first in its kind and represents a premium genetic resource for potato breeding programs and plant biologists for genes functional characterization in potato.

The character of determinate plant growth has not been reported for chickpea and has not been observed in the world germplasm collection at ICRISAT, Patancheru, India. A determinate growth habit would be desirable where growing conditions often lead to excessive vegetative growth. We attempted to generate this trait by mutation breeding. Seeds of the cultivar ICCV 6 were exposed to varying irradiation treatments, M1 and M2 populations were raised, and in the latter one plant was detected that showed the determinate growth habit and female sterility. The character of determinate growth segregated in a postulated digenic epistatic 3:13 fashion in the F2 and confirmed its digenic mode of inheritance in the F3 and F4. The symbol cd is proposed for the allele conditioning for determinancy and Dt for the allele expressing the determinate trait. Continued mutation breeding with this and other material may result in identifying fully fertile, determinate plant types.