A novel locus (Bnsdt2) in a TFL1 homologue sustaining determinate growth in Brassica napus

Background The determinate growth habits is beneficial for plant architecture modification and the development of crops cultivars suited to mechanized production systems. Which play an important role in the genetic improvement of crops. In Brassica napus, a determinate inflorescence strain (4769) has been discovered among doubled haploid (DH) lines obtained from a spring B. napus × winter B. napus cross, but there are few reports on it. We fine mapped a determinate inflorescence locus, and evaluated the effect of the determinate growth habit on agronomic traits. Results In this study, we assessed the effect of the determinate growth habit on agronomic traits. The results showed that determinacy is beneficial for reducing plant height and flowering time, advancing maturity, enhancing lodging resistance, increasing plant branches and maintaining productivity. Genetic analysis in the determinate (4769) and indeterminate (2982) genotypes revealed that two independently inherited recessive genes (Bnsdt1, Bnsdt2) are responsible for this determinate growth trait. Bnsdt2 was subsequently mapped in BC2 and BC3 populations derived from the combination 2982 × 4769. Bnsdt2 could be delimited to an approximately 122.9 kb region between 68,586.2 kb and 68,709.1 kb on C09. BLAST analysis of these candidate intervals showed that chrC09g006434 (BnaC09.TFL1) is homologous to TFL1 of A. thaliana. Sequence analysis of two alleles identified two non-synonymous SNPs (T136C, G141C) in the first exon of BnaC09.TFL1, resulting in two amino acid substitutions (Phe46Leu, Leu47Phe). Subsequently, qRT-PCR revealed that BnaC09.TFL1 expression in shoot apexes was significantly higher in NIL-4769 than in 4769, suggesting its essential role in sustaining the indeterminate growth habit. Conclusions In this study, the novel locus Bnsdt2, a recessive genes for determinate inflorescence in B. napus, was fine-mapped to a 68,586.2 kb - 68,709.1 kb interval on C09. The annotated genes chrC09g006434 (BnaC09.TFL1) that may be responsible for inflorescence traits were found.

Deletion of a cyclin-dependent protein kinase inhibitor, CsSMR1, leads to dwarf and determinate growth in cucumber (Cucumis sativus L.)

Key message A 7.9 kb deletion which contains a cyclin-dependent protein kinase inhibitor leads to determinate growth and dwarf phenotype in cucumber. Abstract Plant architecture is a composite character which are mainly defined by shoot branching, internode elongation and shoot determinacy. Ideal architecture tends to increase the yield of plants, just like the case of “Green Revolution” increased by the application of semi-dwarf cereal crop varieties in 1960s. Cucumber (Cucumis sativus L.) is an important vegetable cultivated worldwide, and suitable architecture varieties were selected for different production systems. In this study, we obtained a novel dwarf mutant with strikingly shortened plant height and determinate growth habit. By bulked segregant analysis and map-based cloning, we delimited the dw2 locus to a 56.4 kb region which contain five genes. Among all the variations between WT and dw2 within the 56.4 kb region, a 7.9 kb deletion which resulted in complete deletion of CsaV3_5G035790 in dw2 was co-segregated with the dwarf phenotype. Haplotype analysis and gene expression analysis suggest that CsaV3_5G035790 encoding a cyclin-dependent protein kinase inhibitor (CsSMR1) be the candidate gene responsible for the dwarf phenotype in dw2. RNA-seq analysis shows that several kinesin-like proteins, cyclins and reported organ size regulators are expressed differentially between WT and dw2, which may account for the reduced organ size in dwarf plants. Additionally, the down-regulation of CsSTM and CsWOX9 in dw2 resulted in premature termination of shoot apical meristem development, which eventually reduces the internode number and plant height. Identification and characterization of the CsSMR1 provide a new insight into cucumber architecture modification to be applied to mechanized production system.

Inheritance of growth habit under photoperiod insensitive genetic background in dolichos bean (Lablab purpureus (L.) Sweet)

Development of high yielding cultivars with determinate growth habit in photoperiod insensitive (PIS) background is one of the major objectives of breeding grain legumes crops including dolichos bean. A thoroughly validated genetic basis is a prerequisite for breeding dolichos bean for determinate growth habit in PIS background. Based on the published reports by researchers of our laboratory and those by others, and our unpublished data, we hypothesized that the number and mode of action of genes controlling growth habit differ with degree of photoperiod sensitivity of the genetic material used to investigate the inheritance of growth habit in dolichos bean. To test this hypothesis, we compared the number and mode of action of genes controlling growth habit between segregating generations in Photoperiod sensitive (PS) and those in PIS genetic backgrounds. While indeterminate and determinate plants segregated in 15:1 ratio in F2 populations derived from crosses between determinate PIS and indeterminate PIS parents, they segregated in 9:7 ratio with indeterminacy being dominant in F2 populations derived from crosses between determinate PIS and indeterminate PS parents. These patterns of segregation (15:1 and 9:7) in favour of indeterminate and determinate plants, respectively in F2 populations were confirmed in F3 populations of PIS and PS genetic backgrounds based on good fit between observed and expected ratios (55:9 and 29:35, respectively) in favour of indeterminate and determinate plants, respectively. The patterns of segregation in F2 populations were further confirmed in F3 populations based on good fit between observed and expected ratios of 3:1 segregating and non-segregating families, and of 3:1 indeterminate and determinate non-segregating families, respectively.

Evaluation of tomato phenological stages passing on multilevel installations «Fitopiramida»

Relevance. Multilevel pipe vegetation installations (MVTU) “Fitopiramida” are designed for hydroponic cultivation of different agricultural crops including tomatoes.Methods. To create F1 tomato hybrids for this technology the assessment of phenological stages passing of tomato lines on “Fitopiramida” MVTU was carried out. 19 breeding lines including 9 cherry tomato lines, 10 large-fruited tomato lines of indeterminate and determinate growth types were tested. These lines were used in various hybridization schemes to obtain F1 tomato heterotic hybrids for “Fitopiramida”.Results. According to the results of the conducted researches in conditions of low-volume technology “Fitopiramida” duration of periods “germination – beginning of flowering” ("G-BF") and “germination – beginning of ripening” ("G-BR") is significantly reduced. In cherry group lines “G-BR” period is shorter by 17.7 days at average, in large-fruited lines by 23-27.3 days at average depending on growth type. The difference in ripening time is more expressed in largefruited lines; border-grown Kb 183 line began ripening 35 days later. Shorter growing season makes it possible to carry out largest number of crop rotations per year to obtain maximum yield per area unit (in full year use greenhouses). Similar results were obtained in the tests of tomato varieties and F1 hybrids on “Fitopiramida” MWTU in 2019-2020 in terms of phenological stages passing acceleration and earlier fruiting of hydroponic grown tomatoes.

DESEMPENHO DE CULTIVARES DE TOMATE ITALIANO DE CRESCIMENTO DETERMINADO EM CULTIVO PROTEGIDO SOB ALTAS TEMPERATURAS

O objetivo desse trabalho foi avaliar a produção, a qualidade e tempo de prateleira de cultivares de tomate tipo italiano de crescimento determinado, produzidos sob ambiente protegido em condições de altas temperaturas. O cultivo foi realizado em Nova Mutum – MT, foram avaliados cinco cultivares: Fascínio (Feltrin sementes), Hy Color (Horticeres), Santa Adélia (TopSeed), SM-16 (Seminis) e Supera F1 (TopSeed), dispostos em blocos casualizados, com quatro repetições. As plantas foram conduzidas em “meia estaca” e não foram podadas. Os parâmetros avaliados foram relativos a produção, a qualidade dos frutos, tempo de prateleira e qualidade no pós-colheita. A cultivar Fascínio apresentou produtividade de 186,1 t ha-1, maior massa média de frutos (144,3g), maior calibre de fruto, (60,7mm), e menor perda de massa no pós-colheita (6,23%). Os melhores resultados de sólidos solúveis totais dos frutos que completaram a maturação na planta foram obtidos das cultivares Santa Adélia (4,3), Fascínio (4,27) e Hy Color (4,21), e dos frutos colhidos no estádio verde-maduro obteve destaque a cultivar Santa Adélia (5,85), e os frutos que ficaram em temperatura ambiente obtiveram maior média de sólidos solúveis totais (5,55). Palavras-chave: termotolerância; Lycopersicum esculentum Mill; produtividade; pós colheita; ambiente protegido. The performance of determinate growth italian tomato cultivars in protected cropping under high temperatures ABSTRACT: This study aimed to evaluate the production, quality and shelf time of determinate growth Italian tomato cultivars from a protected environment under high temperature conditions. The cultivation was conducted in Nova Mutum, state of Mato Grosso, Brazil. Five cultivars were evaluated: ‘Fascínio’ (Feltrin Sementes), ‘Hy Color’ (Horticeres), ‘Santa Adélia’ (TopSeed), ‘SM-16’ (Seminis) and ‘Supera F1’ (TopSeed), disposed in randomized blocks with four repetitions. The plants were managed into the “meia estaca” tutoring method and were not pruned. The parameters evaluated were related to the production, quality of fruits, shelf time and postharvest quality. The ‘Fascínio’ cultivar presented productivity of 186.1 t ha-1, the largest average fruit weight (144.3 g), the largest fruit gauge (60.7 mm) and the smallest postharvest weight loss (6.23%). The total soluble solids best results of fruits that have matured in the plant were obtained from the ‘Santa Adélia’ (4.3), ‘Fascínio’ (4.27) e ‘Hy Color’ (4.21) cultivars. Among the fruits harvested at the mature-green stage, the ‘Santa Adélia’ (5.85) cultivar stood out. The fruits that stayed at room temperature obtained the largest total soluble solids average (5.55). Keywords: thermotolerance; Lycopersicum esculentum Mill; productivity; postharvest; protected environment.

Dynamic Development of White Lupin Rootlets Along a Cluster Root

White lupin produces cluster roots in response to phosphorus deficiency. Along the cluster root, numerous short rootlets successively appear, creating a spatial and temporal gradient of developmental stages that constitutes a powerful biological model to study the dynamics of the structural and functional evolution of these organs. The present study proposes a fine histochemical, transcriptomic and functional analysis of the rootlet development from its emergence to its final length. Between these two stages, the tissue structures of the rootlets were observed, the course of transcript expressions for the genes differentially expressed was monitored and some physiological events linked to Pi nutrition were followed. A switch between (i) a growing phase, in which a normal apical meristem is present and (ii) a specialized phase for nutrition, in which the rootlet is completely differentiated, was highlighted. In the final stage of its determinate growth, the rootlet is an organ with a very active metabolism, especially for the solubilization and absorption of several nutrients. This work discusses how the transition between a growing to a determinate state in response to nutritional stresses is found in other species and underlines the fundamental dilemma of roots between soil exploration and soil exploitation.

Sources and rates of nitrogen on the nutrition and productive performance of determinate growth habit snap bean

Snap bean is a vegetable crop presenting high requirements of mineral nutrients, such as nitrogen (N). However, studies on the response of this crop to N fertilizationare scarce, mainly with determinate growth habit genotypes, making it difficult to manage thisnutrient supply. The aim of this study was to evaluate the nitrogen nutrition and the productive performance of snap bean withdeterminate growth habit as a function of N sources and rates. The experiment was carried out inpots, under greenhouse conditions, inaEutrophicRed Oxisolwith 36.60 g dm-3of soil organic matter content.The cultivar ‘Macarrãorasteiro’TopSeedwas grownin a completely randomized design at factorial scheme 3x4, with four replications. It was studied three sources of N (urea, ammonium sulfate and sulfammo) and four rates (0, 40, 80 and 120 kg N ha-1), applied20% at sowing time, 40% at 12 days after emergence (DAE) and 40% at 20 DAE.It was evaluatedthe N content of the index leafandtheNaccumulationinshoots, the plant height at the endof the cycle and the number, total fresh mass, mean fresh mass and mean length of pods.The N content of the index leaf and N accumulation in shoots were linearly increased by the N rates, regardless of the N source, while the plant height and the pod’s characteristics werenotinfluenced by anyof the factors studied

Genetics of growth habit in horse gram (Macrotyloma uniflorum (Lam.)Verdc.)

Growth habit is a plant architectural trait in grain legumes with no exception of horse gram. Determinacy and indeterminacy are the two types of growth habits reported in horse gram. Relative advantages of the two types of growth habit depend on the production systems to which cultivars are targeted. Dependable information on genetics of growth habit provide clues for adopting the most appropriate selection strategy to breed high yielding horse gram varieties with desired growth habit. Taking cues from the past studies, we hypothesize that growth habit in horse gram is controlled by two genes displaying inhibitory epistasis and indeterminacy is dominant over determinacy. To test this hypothesis, we monitored the inheritance of growth habit in F1, F2 and F3 generations derived from two crosses involving parents differing for growth habit. Contrary to our hypothesis, determinate growth habit of F1s of both the crosses suggested dominance of determinacy over indeterminacy. A good fit of observed segregation of F2 plants to that of the hypothesized segregation in the ratio of 13 determinate: 3 indeterminate plants, besides confirming dominance of determinacy, suggested classical digenic inhibitory epistatic control of growth habit. These results were further confirmed in F3 generation based on goodness of fit between observed numbers of plants segregating for determinacy and indeterminacy and those expected in the ratio of 49 determinate: 15 indeterminate plants. To the best of our knowledge, this is the first report on the inheritance of growth habit in horse gram.