Plant Growth Habit Research Articles

Induction of phenotypic diversity in mutagenized population of lentil (Lens culinaris Medik) by using heavy metal

Pulse breeding has been performed in the past by utilizing the genetic variability using conventional method. At the present time, these techniques are insufficient for producing new cultivars to fulfill globally increased food demand. In this situation, induced mutagenesis have been appeared as a new technique which are largely utilized for evolving improved mutants with good quality of agronomic traits and for determining desired genes that control agronomical traits. In the present investigation lentil seeds were mutagenized with different doses (5, 10, 15, 20 and 25 ppm) of lead and cadmium nitrate. M2 generation was raise from collected seeds of M1 generation. Distinct morphological mutants were selected with different traits such plant height, growth habit, leaf morphology, flower character, pigmentation and pod size. Different meiotic aberration such as stickiness, precocious separation of chromosome, unequal division, disturbed polarity with laggards, cytomixis, disorientation, unpolarized chromosome, sticky metaphase, multinucleate condition with micronuclei were also observed in this experiment. Some mutants may be utililised directly in selection or some of these are beneficial in breeding programme. Beneficial mutants were determined at lower concentrations both heavy metals with highest mutation frequency in cadmium than lead nitrate.

FT/TFL1: Calibrating Plant Architecture.

There is a very large diversity in plant architecture in nature. Over the past few years, novel theoretical concepts and analytical methods have emerged as powerful tools to understand important aspects of plant architecture. Plant architecture depends on the relative arrangement of three types of organs: leaves, shoots, and flowers. During plant development, the architecture is modulated by the balance of two homologous proteins: FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1). The FT/TFL1 balance defines the plant growth habit as indeterminate or determinate by modulating the pattern of formation of vegetative and reproductive structures in the apical and axillary meristems. Here, we present a summarized review of plant architecture and primarily focus on the FT/TFL1 balance and its effect on plant form and development. We also propose passion fruit as a suitable model plant to study the effect of FT/TFL1 genes on plant architecture.

Xylella fastidiosa subsp. pauca and fastidiosa Colonize Arabidopsis Systemically and Induce Anthocyanin Accumulation in Infected Leaves.

The bacterium Xylella fastidiosa is a multihost pathogen that affects perennial crops such as grapevine, sweet orange, and olive tree worldwide. It is inherently difficult to study these pathosystems owing to the long-term growth habit of the host plant. Thus, the availability of model plants becomes essential to accelerate discoveries with economic impact. In this study, we uncovered evidence that the model plant Arabidopsis thaliana can be colonized by two different X. fastidiosa subspecies, pauca and fastidiosa. We observed that these bacteria are able to move away from the inoculation point as high bacterial populations were found in distant tissues. In addition, confocal laser scanning microscopy analysis of bacterial movement inside the petiole revealed the ability of the bacterium to move against the net xylem flow during the time course of colonization forming biofilm. These findings provide evidence for the capacity of X. fastidiosa to colonize Arabidopsis. Furthermore, leaves inoculated with X. fastidiosa showed a significant accumulation of anthocyanin. We propose that the X. fastidiosa subsp. pauca or fastidiosa colonization pattern and anthocyanin accumulation in the Arabidopsis ecotype Col-0 can be used as marker phenotypes to facilitate further studies aimed at improving genetic components involved in X. fastidiosa-host interaction.

The potential breeding value of snow clover (Trifolium pratense ssp. nivale (W.D.J. Koch) Arcang.) and red clover (Trifolium pratense ssp. sativum) hybrids

Eight red clover subspecies are registered in Europe but it can be considered that the high genetic diversity and local genetic adaptation existing at a subspecies level is unused. The experiment aimed at studying agronomical traits of the hybrids obtained from crosses of wild subspecies of Trifolium pratense - snow clover (Trifolium pratense ssp. nivale (W.D.J. Koch) Arcang.) and cultivated red clover (Trifolium pratense ssp. sativum). Under field conditions, two snow clover half-sib families - F1 generation of crossbreeding were selected and compared to the paternal variety Nika 11 for three years. According to results, the size, habit of growth as well as dry matter productivity at spring growth of the F1 hybrids were similar to the cultivated red clover. In summer regrowth, they were less productive. In terms of a type and rate of development the hybrids were similar to snow clover. From morphological point of view, the families proved of interest with its abundant leafiness, which renders them suitable for breeding in pasture direction. The hybrids are characterized by an icreased number of seeds per inflorescence and seed yield. The open-pollinated seeds of families were used for the formation of a population that represented the F2 generation progenies. The phenotypic variation in the first vegetation of F2 generation was high for plant flower colour, growth habit, and degree of pubescence. It can be considered that this population contains a high genetic variation and is suitable for development of complex hybrid breeding populations.

Crop Evolution and Domestication Syndromes

Crops evolved through evolution and domestication process and different crops either have different or similar origin. Evolution and domestication process is progressing process starting with wild species, then formation of cultivated one and selection of improved strain of the species by growers and researchers. These processes may happen due to mutation, immigration, artificial selection, natural selection, speciation and cross. Evolution and domestication process then results difference among domesticated as well as evolved crops from their wild progenitors and this coined as syndromes. The syndromes discussed in this paper includes plant height and growth habit, flowering time inflorescence size and morphology, fruit size and morphology, organ color and toxic substance, seed size and dispersal and seed dormancy. As future direction, studying the wild species more and more and maintaining them enables to develop crops that are resist to biotic or abiotic stresses and obtaining yielding crops varieties. Keywords : Crop, Evolution, Domestication, Syndrome DOI : 10.7176/JNSR/9-12-01 Publication date :June 30 th 2019

Seed yield in perennial ryegrass (Lolium perenne L.): comparative importance of component traits and detection of seed-yield-related QTL

The aims of our study were to evaluate relationships amongst morphological traits associated with seed production in a perennial ryegrass biparental population and to identify genomic regions associated with phenotypic variation in those traits using QTL analysis. This was achieved using data from two field experiments at Palmerston North and Lincoln, New Zealand, in 2003, and days to heading (DTH), reassessed in 2004. Trait association was determined for the Palmerston North experiment where measured traits included seed yield per plant (SYPlant), seed yield per spike (SYSp), reproductive tiller number (RTiller), spikelets per spike (SpktSp), florets per spikelet (FSpkt), 1000 seed weight (TSW), spike length (SpLen), florets per spike (FSp), floret site utilization (FSUtil), spread of heading (SOH) and plant growth habit (PGHabit). Traits contributing to SYPlant in order of descending value were FSpkt, FSUtil, and RTiller. High TSW was only weakly linked to SYPlant. FSUtil, SOH and RTiller were identified as valuable breeding targets for improving seed yield potential in perennial ryegrass. QTL were identified for all traits except for RTiller. QTL for SYPlant occurred on linkage groups (LG) 2 and 6. Both were co-located with QTL for SYSp and sets of SYPlant components or related traits (FSpkt, FSp; FSUtil and TSW). Major QTL for DTH were identified on LG2 and LG4 and minor QTL on LG7 in consecutive years. There was a strong genotype-by-environment interaction for SYPlant that was reflected in a lack of consistent QTL across environments, while QTL for SYSp and DTH were stable across environments. Identification of component traits and QTL important for seed yield may accelerate genetic improvement in perennial ryegrass through conventional and marker-assisted breeding, respectively.

Agro-morphological description, genetic diversity and population structure of sugarcane varieties from sub-tropical India.

Genetic diversity in 92 sugarcane varieties of sub-tropical India was assessed using 30 morphological descriptors and 643 simple sequence repeat (SSR) marker loci. Out of the 30 morphological descriptors, 14 were found polymorphic, and significant variability was recorded for plant height, cane diameter and number of millable canes. Grouping traits like plant growth habit, leaf blade curvature and leaf sheath adherence were found to be predominantly monomorphic. There were a few pairs of varieties (e.g., CoP 9702 and CoP 9302, CoP 9301 and CoSe 01424, UP 05 and Co 1336, CoS 96258 and CoH 110) that showed similar DUS profiles except differing for a few descriptors. The STRUCTURE profile suggest that all the 92 sugarcane varieties had admixtures and no sub-group had a pure unblemished structure profile. An average Nei's genetic distance of 0.49 was found to be a better measure of diversity, whereas, the average band informativeness (Ibav) value of all the 80 SSR primers was 0.434. Although, the mean Ibav values for EST-SSR and genomic-SSR primers were same (0.43), the range of Ibav of EST-SSR (0.04-0.85) was more compared to genomic-SSR (0.12-0.63) primers. The segregation of the varieties based on morphological traits was not in accordance with their geographical distribution or maturity groups, but principal component analysis was able to group thesugarcane varieties that had similar pedigree together. Results indicate that the SSRs have a potential use in the DNA fingerprinting of varieties to prevent any malpractice like unauthorised re-registration of a previously registeredsugarcane variety under PPV&FR Act. The marker profiles could also be utilised for variety identification and release, since at present, it has been made mandatory to include it in addition to the morphological descriptors.

Plastic biomass allocation as a trait increasing the invasiveness of annual bluegrass (Poa annua L.) in Antarctica

The plasticity of functional traits promotes invasiveness of a species. Biomass allocation, as one of these traits, is responsible for resource acquisition, and its plastic modifications can be of adaptive value in new environments before any genetic adaptations may occur. Our aim was to compare in situ biomass allocation in aboveground and belowground organs in an Antarctic and a Polish population of annual bluegrass (Poa annua), the only alien plant species successfully invading Antarctica. The Antarctic population was characterised by three times lower aboveground biomass, more compact plant growth habit and higher fraction of biomass allocated into belowground organs than in the Polish population. The differences between populations are probably a result of adaptation to local conditions. The modifications of the studied traits in the Antarctic population are most likely a response to extreme atmospheric and edaphic conditions and enable the species to survive and spread in this hostile environment. Our results are in accordance with the balanced growth hypothesis. At the same time, these trait values enhance species performance under Antarctic conditions making P. annua a potential threat to local plant communities under altering climate changes and growing human impact scenario.

Nulliplex-branch, a TERMINAL FLOWER 1 ortholog, controls plant growth habit in cotton.

Nulliplex-branch (nb) mutants in cotton display a specific architecture. The gene responsible for the nb phenotype was identified, and its modulation mode was further studied. Plant architecture is an important agronomic factor influencing various traits such as yield and variety adaptability in crop plants. Cotton (Gossypium) simultaneously displays monopodial and sympodial growth. Nulliplex-branch (nb) mutants showing determinate sympodial shoots have been reported in both G. hirsutum (Ghnb) and G. barbadense (Gbnb). In this study, the gene responsible for the nb phenotype was identified. GhNB and GbNB were found to be allelic loci and are TERMINAL FLOWER 1 orthologs on the Dt subgenome, though the At copies remain native. Sequencing and association analyses identified four (Gh-nb1-Gh-nb4) and one (Gb-nb1) type of point mutation in the coding sequences of Ghnb and Gbnb, respectively. The NB gene was mainly expressed in the root and shoot apex, and expression rhythms were also observed in these tissues, suggesting that the expression of the NB gene could be regulated by photoperiod. Constitutive overexpression of GhNB suppresses the differentiation of the reproductive shoots. Knockout of both copies of GhNB caused the main and lateral shoots to terminate in flowers, which is a more determinate architecture than that of the nb mutants and implies that its function might be dosage dependent. A protein lipid overlay assay indicated that the amino acid substitutions in Gh-nb1 and Gb-nb1 weaken the ligand-binding activity of the NB protein in vitro. These findings suggest that the NB gene plays crucial roles in regulating the determinacy of shoots, and the modulation of this gene should constitute an effective crop improvement approach through adjusting the growth habit of cotton.

Characterization and genetic diversity of brinjal germplasm

The experiment was carried out in a non replicated design with 40 accessions of brinjal (Solanum melongena L.) at Plant Genetic Resources Centre (PGRC), BARI Gazipur to characterize and study the genetic diversity and identify the useful traits. Each accession of nine plants was grownin a 3 X 2 m size plot. The accessions were collected from 16 districts of Bangladesh. Two to four classes were found for plant growth habit, leaf blade lobing, leaf prickles, flower colour, fruit shape, fruit apex shape and fruit colour distribution. The accessions exhibited 64% straight, 13% both slightly curved and curved, and 10% snaked shaped edible fruit along with 55% purple and 45% green fruit. Fruit length of accessions ranged from 5 to 31.23 cm, breadth 2.4 to 10.6 cm, weight 13 to 95.2 g and 3 to 30 fruits per plant. The accessions were grouped into five clusters. The inter and intra cluster distances ranged from 4.01 to 8.32 and 0.94 to 1.36, respectively. Accessions collected from the same districts felt into different clusters. The results obtained by D2 analysis were also confirmed by canonical analysis. Crosses BD-7327 (Rangpur) of cluster II with BD-9954 (Chittagong) of Cluster-III and BD-7319 (Panchagarh) of Cluster-I with BD-11732 (Bandarban) of cluster V, could be performed for obtaining wider variability in the segregating generations. The breeders could use the selected accessions for varietal improvement of brinjal.Bangladesh J. Agril. Res. 43(3): 499-512, September 2018

The Genus Nolina (Asparagaceae) of the Baja California Peninsula, and the Recognition of a New Species Combination

The genus Nolina on the Baja California peninsula has not been critically studied. Most of the taxonomic literature dealing with this group is older or incomplete in nature. Taxonomic problems with this genus arise because it is not easy to make herbarium specimens from plants in the field and the taxa are not well represented in collections. Species in this genus are difficult because they are dioecious, generally have large rosettes with many leaves, leaf margins that often cut skin, and the plants have large inflorescences. On older herbarium specimens, it is common to find only a leaf and an inflorescence fragment, and labels often do not provide taxonomically important information such as the plant's growth habit type. Consequently, distinctive inflorescence characters are usually missing from the specimen or from the label data. It is rare to find a complete specimen collection that includes all of the needed species-relevant data. Decisions for delimiting species in this genus are not easy, and in this case, were based mostly upon their morphological character consistency, geographic distribution, and environmental factors. Five species of Nolina are now registered for the Baja California peninsula: N. beldingii, N. bigelovii, N. interrata, N. palmeri, and the new nomenclatural combination N. brandegeei (Trelease) L. Hern. This paper includes: a species identification key, species taxonomic descriptions, ecological and geographical information, common names, taxonomic discussions of species, and pictures for species recognition of all taxa in the Baja California region.

Transgressive segregations for agronomic improvement using interspecific crosses between C. arietinum L. x C. reticulatum Ladiz. and C. arietinum L. x C. echinospermum Davis species.

The wild species of chickpea have tremendous potential for enhancing genetic gains of cultigen and have resistant accessions against major biotic and abiotic stresses. In the present study, two wild annual accessions, one each of C. reticulatum Ladiz. (ILWC 229) and C. echinospermum Davis (ILWC 246) were assessed for their agro-morphological features and hybridized with different cultivated varieties (BGD 72, PBG 5, ICKG 96029, Pusa 372 and JG 11) of chickpea. Fertile F1 plants were developed as revealed by their normal meiotic chromosomal configuration including high pollen stainability percentage and seed set. The effect of genetic and non-genetic factors on crossability performance with respect to pod and seed set was also evident under two growing conditions of North-Western Indian Himalayas. The segregation analysis using F2 phenotypic ratio of some distinct morphological (plant growth habit, stem pigmentation at seedling stage and testa texture) characters indicated their monogenic inheritance pattern. The study would also be useful to chickpea breeders to identify true to type interspecific plants. Further, the F1, F2 and F3 generations of all seven crosses along with parents were evaluated under natural field condition to determine the extent of variability created into the cultivated background of chickpea. There was a wide range of variation in F3 population against cold stress, suggesting selection of tolerant recombinant lines at an early stage. We also studied fruitful heterosis (%) as a useful approach, instead of residual heterosis to identify better performing transgressive segregants. The values of most of the interspecific crosses for important traits assessed in F2 and F3 generations were higher than that of better parent, suggesting isolation of inbred vigour for pod numbers and earliness. The results indicated that wild Cicer annual accessions of C. reticulatum and C. echinospermum species can be exploited after proper screening for traits of interest for diversification of cultivated gene pool and subsequent use in chickpea improvement.

Validation of QTLs for plant ideotype, earliness and growth habit traits in pigeonpea (Cajanus cajan Millsp.).

Pigeonpea productivity is greatly constrained by poor plant ideotype of existing Indian cultivars. Enhancing pigeonpea yield demands a renewed focus on restructuring the ideal plant type by using more efficient approaches like genomic tools. Therefore, the present study aims to identify and validate a set of QTLs/gene(s) presumably associated with various plant ideotype traits in pigeonpea. A total of 133 pigeonpea germplasms were evaluated along with four checks in the augmented design for various ideotype traits i.e. initiation of flowering (IF), days to 50% flowering (DFF), days to maturity (DM), plant height (PH), primary branches (PB), seeds per pod (SP) and pod length (PL). We observed significant genetic diversity in the germplasm lines for these traits. The genetic control of IF, DFF, DM and PH renders these traits suitable for detection of marker trait associations. By using residual maximum likelihood algorithm, we obtained appropriate variance-covariance structures for modeling heterogeneity, correlation of genetic effects and non-genetic residual effects. The estimates of genetic correlations indicated a strong association among earliness traits. The best linear unbiased prediction values were calculated for individual traits, and association analysis was performed in a panel of 95 diverse genotypes with 19 genic SSRs. Out of five QTL-flanking SSRs used here for validation, only ASSR295 could show significant association with FDR and Bonferroni corrections, and accounted for 15.4% IF, 14.2% DFF and 16.2% DM of phenotypic variance (PV). Remaining SSR markers (ASSR1486, ASSR206 and ASSR408) could not qualify false discovery rate (FDR) and Bonferroni criteria, hence declared as false positives. Additionally, we identified two highly significant SSR markers, ASSR8 and ASSR390 on LG 1 and LG 2, respectively. The SSR marker ASSR8 explained up to 22 and 11% PV for earliness traits and PB respectively, whereas ASSR390 controlled up to 17% PV for earliness traits. The validation and identification of new QTLs in pigeonpea across diverse genetic backgrounds brightens the prospects for marker-assisted selection to improve yield gains in pigeonpea.

Morphological and molecular characterization of two distinct chilli cultivars from North Eastern India with special reference to pungency related genes

Abstract King chilli and Dalle Khursani are the two hottest chilli (Capsicum sp.) cultivars widely grown in NE region of India but a well-organized study pertaining to King chilli and Dalle Khursani is unavailable. We have characterized twenty-two accessions of King chilli and Dalle Khursani, collected from different states of NE region with respect to 27 morphological parameters and using 30 SSR markers. The allelic status of three key pungency related genes viz, putative aminotransferase (pAmt or Pun1), acyl-CoA synthetase (Acs1) and β-ketoacyl-ACP synthase (Kas1) was also determined. Maximum morphological variation was observed for fruit traits and traits like plant growth habit, plant height, etc., which can be used to distinguish between the two cultivars. SSR markers HpmsE062 and HpmsE063 were able to distinguish between the three different cultivars (including a nonpungent bell pepper), while HpmsE116 and HpmsE139 distinguish King chilli from Dalle Khursani. Ward clustering method grouped all the eleven Dalle Khursani accessions together with non-pungent C. annuum accession in one cluster. Sequencing across Acs1 revealed total of eight SNPs and three InDels. Seven SNPs including three within exonic regions were conserved between bell pepper, Dalle Khursani and the reference pungent C. annuum accession. A 2 bp InDel at position 50–51 bp and a 3 bp InDel at position 6313–6315 bp were found to be uniquely conserved haplotypes in both Dalle Khursani and King Chilli. A total of 16 SNPs were found within the sequenced region of Pun1 gene, of which eight SNPs lie within the coding region. Three novel exonic SNPs were found in Dalle Khursani. All eight SNPs found in the intronic region for Pun1 were conserved across Dalle Khursani and the two pungent reference sequences of C. annuum. Our SSR and SNP data suggests that Dalle Khursani is genetically closer to pungent C. annuum. This work provides insights into the genotype of two hottest chillies and paves way for their utilization in chilli improvement programme.

Divergence analysis of black gram (Vigna mungo L.) for grain yield and yield components

Thirty-two black gram genotypes were evaluated using twelve quantitative and fifteen qualitative traits at Motilal Nehru National Institute of Technology (MNNIT), Allahabad, India to determine genetic divergence using important yield and yield contributing traits. The number of pods plant-1, peduncle length, harvest index and biomass yield plant-1 are important traits affecting grain yield response in black gram. The quantitative traits like; pod length, number of pods plant-1, 100-grain weight as well as qualitative traits like; stem pubescence, leaf pubescence, pod pubescence, pre mature pod colour and plant growth habit which have major contribution in the genetic divergence of black gram. The number of pods plant-1 is most important grain yield contributing and genetic divergence developing traits. The genotypes were classified into six clusters based on Euclidean distance. The genotypes belonging to cluster I, II and III were highly diverse than genotypes lies in cluster IV, V and VI. The genotypes IPU 99-176, UH 82-51, GE 154, IPU 99-3 and NG 2119 had good potential to develop high yielding transgressive segregants. The wide genetic diversity is present in black gram. The present study will be much helpful for selection of the parental lines to develop good grain yield producing black gram cultivar in accordance with changing climate.

SELF-PRUNING Acts Synergistically with DIAGEOTROPICA to Guide Auxin Responses and Proper Growth Form.

The SELF PRUNING (SP) gene is a key regulator of growth habit in tomato (Solanum lycopersicum). It is an ortholog of TERMINAL FLOWER1, a phosphatidylethanolamine-binding protein with antiflorigenic activity in Arabidopsis (Arabidopsis thaliana). A spontaneous loss-of-function mutation (sp) has been bred into several industrial tomato cultivars, as it produces a suite of pleiotropic effects that are favorable for mechanical harvesting, including determinate growth habit, short plant stature, and simultaneous fruit ripening. However, the physiological basis for these phenotypic differences has not been thoroughly explained. Here, we show that the sp mutation alters polar auxin transport as well as auxin responses, such as gravitropic curvature and elongation of excised hypocotyl segments. We also demonstrate that free auxin levels and auxin-regulated gene expression patterns are altered in sp mutants. Furthermore, diageotropica, a mutation in a gene encoding a cyclophilin A protein, appears to confer epistatic effects with sp Our results indicate that SP affects the tomato growth habit at least in part by influencing auxin transport and responsiveness. These findings suggest potential novel targets that could be manipulated for controlling plant growth habit and improving productivity.

AGRONOMIC PERFORMANCE OF COWPEA ELITE LINES IN THE STATES OF MINAS GERAIS AND MATO GROSSO, BRAZIL

ABSTRACT The objective of this work was to evaluate the agronomic performance of erect and semi-erect cowpea elite lines grown in the States of Minas Gerais and Mato Grosso, Brazil. The experiments were conducted in Jaíba, Janaúba, Sete Lagoas (Minas Gerais), Primavera do Leste and Nova Ubiratã (Mato Grosso), with 20 genotypes of cowpea, arranged in a randomized block design with four replications. The data were subjected to individual and joint analyses of variance and means grouped by the Scott-Knott test (p<0.05). The plant growth habit, lodging, cultivation value, pod length and bean yield were evaluated. The lines MNC04-768F-21 and MNC04F-795F-168 had the highest bean yield in the experiments conducted in Mato Grosso, and their growth habit, lodging and cultivation value were similar to those of the cultivar BRS-Guariba. The lines MNC04-769F-30, MNC05-795F-154 and MNC04-769F-49 and the cultivar BRS-Tumucumaque had the highest bean yield in the experiments conducted in Minas Gerais. However, the cultivars BRS-Guariba, BRS-Tumucumaque, BRS-Novaera, BRS-Itaim and BRS-Cauamé and the lines MNC04-792F-143 and MNC04-792F-144 showed satisfactory bean yield and good growth habit, plant lodging and cultivation value in the State of Minas Gerais, especially in the northern region of the state (Jaíba and Janaúba), representing good alternatives for the genotypes recommended for this region.

Elucidation of diversity among $$\hbox {F}_{1}$$ F 1 hybrids to examine heterosis and genetic inheritance for horticultural traits and ToLCV resistance in tomato

Genetic diversity during prebreeding or postbreeding programme, is the key pillar to characterize the valuable traits and gene of interest. Whereas, superior or inferior heterotic performance of F1 depend on the diverse nature of their pedigree. Therefore, the aim of this study was to see the diversity between the interspecific crosses and effect of heterosis, and inheritance for the morphological traits and ToLCV resistance. All the 24 F1 interspecific crosses were classified into four clusters on the basis of morphological traitsas well as simple sequence repeat (SSR) markers. Among the F1 hybrids, 23 were grouped into clusters II, III and IV with different phylogeny, while PBC×EC 521080 was individual with cluster I. On the basis of visual observation of fruit colour, deep red and green colours in the crosses of S. pimpinellifolium (EC 521080) and S. habrochaites (EC 520061) exhibited dominant effects. In context of heterosis breeding, the crosses which were made using Solanum pimpinellifolium (EC 521080), S. chmielewskii (EC 520049) and S.cerasiforme (EC 528372) were better for yield capacity and the crosses of S. habrochaites (EC 520061) exhibited low and negative heterosis for ToLCV resistance. The F1 progenies were segregated in various Mendelian ratio as follows 3:1, 1:2:1, 1:3, 13:3, 15:1, 12:3:1 and 9:6:1 for ToLCV disease reaction of incidence, plant growth habit and fruit colour appearance, respectively. Therefore, these interspecific crosses can be utilized for developing high yield, impressive fruit colour combiners and resistant hybrids/varieties of tomato.

POPULATION DENSITY ON COWPEA CULTIVARS WITH DIFFERENT GROWTH HABITS IN THE MATOPIBA REGION

ABSTRACT The aim of this study was to assess the productive performance of cowpea cultivars with different growth habits as a function of population density in the MATOPIBA region, Brazil. The experiments were carried out in Magalhães de Almeida, MA in the agricultural season 2014/2015. The cultivars BRS Itaim, BRS Tumucumaque, and BRS Pajeú, which present an erect, semi-erect, and semi-prostrate growth habits, respectively, were assessed. For the erect and semi-erect cultivars, a total of 8, 12, 16, 20, 24, and 28 plants m−2 were used whereas for the semi-prostrate cultivar, a total of 2, 6, 10, 14, 18, and 22 plants m−2 were used. The experimental design was a randomized block design with four replications and treatments composed of plant densities. Grain yield and number of pods per area presented a quadratic response to the increased plant density whereas a decreasing linear response was observed for the number of pods per plant. The maximum grain yield of erect, semi-erect, and semi-prostrate cultivars were 1,076 kg ha−1 (19.5 plants m−2), 1,252 kg ha−1 (18.7 plants m−2), and 755 kg ha−1 (14.5 plants m−2), respectively. The number of pods per area was the character that most correlated (P<0.01) with grain yield, regardless of the plant growth habit.

Linear discriminant analysis of structure within African eggplant ‘Shum’

African eggplant (Solanum aethiopicum) lags behind in terms of research attention; leading to, among other gaps, scantiness of information on intra-group genetic diversity. Hierarchical clustering was applied to reveal structure in a pioneer 20-entry set of S. aethiopicum Shum group accessions at Africa Solanaceae Research Network secretariat in Uganda, using 61 morpho-agronomic variables collected from a complete randomised design (CRD) with 12 plants per accession in screen-house. A MANOVA preceded linear discriminant analysis, to model each of 61 variables, as predicted by clusters and experiment to filter out non-significant traits. Four distinct clusters emerged, with a cophenetic relation coefficient of 0.87 (P<0.01). Canonical variates that best predicted the observed clusters include petiole length, sepal length (or seed colour), fruit calyx length, seeds per fruit, leaf fresh weight (or leaves per plant), fruit fresh yield, seedling vigour, fruits per plant, harvest index and plant growth habit. Results suggest prospects for variety discrimination at various stages; seedling, vegetative and reproductive. The observed diversity will boost chances of effective selection for desired traits; while the canonical discriminant traits are potential morphological markers, within S. aethiopicum ‘Shum’ for a low-cost germplasm characterisation approach. Key words: Hierarchical clustering, morphological markers, Solanum aethiopicum