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.

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.

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.

Sink Strength Maintenance Underlies Drought Tolerance in Common Bean

Drought is a major limiter of yield in common bean, decreasing food security for those who rely on it as an important source of protein. While drought can have large impacts on yield by reducing photosynthesis and therefore resources availability, source strength is not a reliable indicator of yield. One reason resource availability does not always translate to yield in common bean is because of a trait inherited from wild ancestors. Wild common bean halts growth and seed filling under drought and awaits better conditions to resume its developmental program. This trait has been carried into domesticated lines, where it can result in strong losses of yield in plants already producing pods and seeds, especially since many domesticated lines were bred to have a determinate growth habit. This limits the plants ability to produce another flush of flowers, even if the first set is aborted. However, some bred lines are able to maintain higher yields under drought through maintaining growth and seed filling rates even under water limitations, unlike their wild predecessors. We believe that maintenance of sink strength underlies this ability, since plants which fill seeds under drought maintain growth of sinks generally, and growth of sinks correlates strongly with yield. Sink strength is determined by a tissue’s ability to acquire resources, which in turn relies on resource uptake and metabolism in that tissue. Lines which achieve higher yields maintain higher resource uptake rates into seeds and overall higher partitioning efficiencies of total biomass to yield. Drought limits metabolism and resource uptake through the signaling molecule abscisic acid (ABA) and its downstream affects. Perhaps lines which maintain higher sink strength and therefore higher yields do so through decreased sensitivity to or production of ABA.

TOMATOES USED BY INDUSTRIES HAVE TECHNOLOGICAL QUALITY FOR FRESH CONSUMPTION1

ABSTRACT The production of tomato (Solanum lycopersicum L.) for fresh consumption must overcome a challenge: the high production cost. The use of cultivars with determinate growth habit is an alternative to reduce costs. Thus, the objective this work was to evaluate the acceptability of tomato fruits from cultivars with determinate growth habit for fresh consumption. Seeds of 10 hybrids and one variety were grown in open field, arranged in six randomized block design, and tested for sensorial acceptability. The analyses were carried out using 50 not-trained consumers, considering their visual and sensorial preferences by affective methods and purchase intention. The hybrid Thaise grown with and without staking and the hybrid Gabrielle grown with staking had higher visual preference by the consumers, with frequency of 24%, 18%, and 22%, respectively, in the first position; and the hybrid Dominador showed higher frequency (18%) in the second and third positions; these hybrids had purchase intention above 80%. All hybrids and varieties had significant difference in the mean test at p<0.05. The highest means found for Carrara, HM7885, Santa Cruz Kada, Asti, N901, Dominador, and Equatorial (appearance); Asti and N901 (color), Asti, Dominador, and Equatorial (aroma), and Santa Cruz Kada, Asti, Dominador, and Equatorial (flavor). Asti, Gabrielle (grown without staking), HM7885, and Equatorial had purchase intention above of 50%. The hybrids Ap533, Portinari, and Thaise grown without staking showed acceptability index lower than 70%. Plants with determinate growth habit produce fruits with acceptable visual and sensorial qualities for fresh consumption.

Productivity, acylsugar concentrations and resistance to the two-spotted spider mite in genotypes of salad tomatoes

ABSTRACT The objective of this study was to characterize genotypes of the salad-type tomato with a determinate growth habit and select genotypes resistant to the two-spotted spider mite for higher productivity and fruit quality. The experiment was conducted at the Horticultural Experimental Station (18°42’43.19” S and 47°29’55.8” W, 873 m altitude) of the Universidade Federal de Uberlândia (UFU), Monte Carmelo campus, from January to June 2018. The experimental design was in randomized blocks containing 16 treatments [12 populations of the F3RC2 generation and four controls: two commercial cultivars (Santa Clara and Rio Grande), the recurrent parent (UFU-057) and the wild species Solanum pennellii (LA-716)] with three repetitions. The accessions UFU-057F3RC210#3.6.1 and UFU-057F3RC213#2.1.2 have high potential for genetic improvement regarding resistance to the two-spotted spider mite. The genotypes UFU-13#4.4.1, UFU-7#4.7.1, UFU-7#4.3.2, UFU-13#2.5.2 and UFU-13#2.1.3 present higher acylsugar concentrations than S. pennellii, in addition to higher productivity and number of fruits per plant. It is suggested to explore combinations between those genotypes previously described with UFU-8#2.4.1 to obtain hybrids with high acylsugar concentrations, two-spotted spider mite resistance, high productivity and increased fruit mass.

DEFOLIATION LEVELS AT VEGETATIVE AND REPRODUCTIVE STAGES OF SOYBEAN CULTIVARS WITH DIFFERENT RELATIVE MATURITY GROUPS

ABSTRACT Soybean tolerance to defoliation may be affected by relative maturity group (RMG) of the cultivar. For this reason, this study was carried out to evaluate the effects of artificial defoliation at vegetative and reproductive stages on the agronomic performance of soybean cultivars with different RMG. Two experiments were carried out in greenhouse conditions in Lages, Santa Catarina State, Brazil. Defoliation was carried out at V6 in the first experiment and at R3 in the second experiment. Three cultivars with contrasting RMG were used: BMX Veloz (RMG of 5.0, indeterminate growth habit), NA 5909 (RMG of 5.9, indeterminate growth habit), and TMG 7262 (RMG of 6.2, semi-determinate growth habit). Each cultivar was submitted to five defoliation levels: 0.0, 16.6, 33.3, 50.0, and 66.6%. Leaf expansion after defoliation, grain yield and its components were determined. The BMX Veloz showed lower leaf expansion capacity and lower grain yield when compared to the other cultivars when defoliated at V6. Grain yield of the three cultivars only showed significant decreases with defoliation levels higher than 16.6% at R3. The cultivar BMX Veloz is less tolerant to defoliation during the vegetative stage when compared to the cultivars NA 5909 and TMG 7262. Cultivar maturity group does not interfere with soybean tolerance to defoliation at the reproductive stage in greenhouse conditions.

Determinate growth habit of grain legumes: role in domestication and selection, genetic control

This review is devoted to the analysis of molecular genetic mechanisms of controlling the type of growth habit of grain legumes (pea, soybean, common bean, vigna); it provides information on the known homologous genes TFL1, LFY, AP1, FUL, FT, and FD. Significant changes in plant architecture were during domestication of grain legumes. Many wild relatives of legumes are characterized by an indeterminate growth habit type, cultivated plants are characterized by indeterminate and determinate types. In plants with a determinate growth habit type, terminal inflorescence is formed at transition from the vegetative phase to the reproductive phase. These plants are characterized by a complex of features: simultaneous maturation of beans, resistance to lodging, etc. In indeterminate type of growth habit, the apical shoot meristem remains active during plant life. The main genes responsible for the plant transition to flowering are the homologs of the Arabidopsis genes LFY, TFL1, AP1. TFL1 gene is responsible for maintaining of growth of the shoot apical meristem; its homologs were identified in pea (PsTFL1a), soybean (Dt1/ GmTfl1), common bean (PvTFL1y), cowpea (VuTFL1). The identification and characterization of the genes responsible for the type of stem growth habit are necessary for the successful selection of modern varieties suitable for mechanized cultivation. Design of molecular markers that diagnose this important breeding trait at early plant development stages, will help determine the type of stem growth habit.

Buckwheat breeding and production in Russia during the past 100 years

Average buckwheat yield in Russia has increased from 0.49 to 0.94 t/ha (1.9 times) in the period from the 1960s to 2011-2017, which is comparable to the growth of wheat yields for the same period (2.1 times, from 1.18 to 2.42 t/ha). However, if the growth in wheat yields occurred gradually, the entire growth of buckwheat yield falls on the beginning of the 21st century. Such differences in dynamics indicate that the increase in buckwheat yield is not related to the improvements in agricultural technology or climate changes. Nor it is related to any significant changes in the structure of buckwheat sowing regions, as the average yield in the most important region of buckwheat cultivation, Altai Territory, is only 0.91 t/ha (i. e. less than the country’s average). Chronologically, the period of an abrupt increase in the yield of buckwheat in Russia coincides with widespread introduction of cultivars with determinate growth habit (determinants). Since 1999, the share of determinant varieties in the total area under buckwheat in Russia has increased from 8.2 to 56.7%. Apparently, it was a main cause for the significant growth of buckwheat yield in Russia. Determinant cultivars based on the d (det) mutation are characterized by reduced plant height, reduced number of flowers on shoots, and more intensive and fast blossoming of inflorescences (and, consequently, more intensive and fast maturation). The increased morphological potential of productivity (the number of vegetative nodes on the stem and first – order branches) ensures a higher level of yield for these cultivars. At present, our lab is developing determinant buckwheat cultivars using some additional mutations. A major success in this work has been the world’s first determinant cultivar with green flowers (the gc mutation) named ‘Design’, which develops thicker and stronger fruit stalks with higher resistance to seed shattering.