Transcriptome and Physiological Analysis of Rapeseed Tolerance to Post-Flowering Temperature Increase.

Climate-change-induced temperature fluctuations pose a significant threat to crop production, particularly in the Southern Hemisphere. This study investigates the transcriptome and physiological responses of rapeseed to post-flowering temperature increases, providing valuable insights into the molecular mechanisms underlying rapeseed tolerance to heat stress. Two rapeseed genotypes, Lumen and Solar, were assessed under control and heat stress conditions in field experiments conducted in Valdivia, Chile. Results showed that seed yield and seed number were negatively affected by heat stress, with genotype-specific responses. Lumen exhibited an average of 9.3% seed yield reduction, whereas Solar showed a 28.7% reduction. RNA-seq analysis of siliques and seeds revealed tissue-specific responses to heat stress, with siliques being more sensitive to temperature stress. Hierarchical clustering analysis identified distinct gene clusters reflecting different aspects of heat stress adaptation in siliques, with a role for protein folding in maintaining silique development and seed quality under high-temperature conditions. In seeds, three distinct patterns of heat-responsive gene expression were observed, with genes involved in protein folding and response to heat showing genotype-specific expression. Gene coexpression network analysis revealed major modules for rapeseed yield and quality, as well as the trade-off between seed number and seed weight. Overall, this study contributes to understanding the molecular mechanisms underlying rapeseed tolerance to heat stress and can inform crop improvement strategies targeting yield optimization under changing environmental conditions.

Transcriptome Analysis of Seed Weight Plasticity in Brassica napus.

A critical barrier to improving crop yield is the trade-off between seed weight (SW) and seed number (SN), which has been commonly reported in several crops, including Brassica napus. Despite the agronomic relevance of this issue, the molecular factors involved in the interaction between SW and SN are largely unknown in crops. In this work, we performed a detailed transcriptomic analysis of 48 seed samples obtained from two rapeseed spring genotypes subjected to different source-sink (S-S) ratios in order to examine the relationship between SW and SN under different field conditions. A multifactorial analysis of the RNA-seq data was used to identify a group of 1014 genes exclusively regulated by the S-S ratio. We found that a reduction in the S-S ratio during seed filling induces the expression of genes involved in sucrose transport, seed weight, and stress responses. Moreover, we identified five co-expression modules that are positively correlated with SW and negatively correlated with SN. Interestingly, one of these modules was significantly enriched in transcription factors (TFs). Furthermore, our network analysis predicted several NAC TFs as major hubs underlying SW and SN compensation. Taken together, our study provides novel insights into the molecular factors associated with the SW-SN relationship in rapeseed and identifies TFs as potential targets when improving crop yield.

Shoot and Root Traits Contribute to Drought Resistance in Recombinant Inbred Lines of MD 23-24 × SEA 5 of Common Bean.

Drought is the major abiotic stress factor limiting yield of common bean (Phaseolus vulgaris L.) in smallholder systems in Latin America and eastern and southern Africa; where it is a main source of protein in the daily diet. Identification of shoot and root traits associated with drought resistance contributes to improving the process of designing bean genotypes adapted to drought. Field and greenhouse studies were conducted at the International Center for Tropical Agriculture (CIAT), Palmira, Colombia to determine the relationship between grain yield and different shoot and root traits using a recombinant inbred lines (RILs) population (MD23-24 × SEA 5) of common bean. The main objectives of this study were to identify: (i) specific shoot and root morpho-physiological traits that contribute to improved resistance to drought and that could be useful as selection criteria in breeding beans for drought resistance; and (ii) superior genotypes with desirable shoot and root traits that could serve as parents in breeding programs that are aimed at improving drought resistance. A set of 121 bean genotypes (111 RILs, 2 parents, 8 checks) belonging to the Mesoamerican gene pool and one cowpea variety were evaluated under field conditions with two levels of water supply (irrigated and rainfed) over three seasons. To complement field studies, a greenhouse study was conducted using plastic cylinders with soil inserted into PVC pipes, to determine the relationship between grain yield obtained under field conditions with different root traits measured under greenhouse conditions. Resistance to drought stress was positively associated with a deeper and vigorous root system, better shoot growth, and superior mobilization of photosynthates to pod and seed production. The drought resistant lines differed in their root characteristics, some of them with a vigorous and deeper root system while others with a moderate to shallow root system. Among the shoot traits measured, pod harvest index, and seed number per area could serve as useful selection criteria for assessing sink strength and for genetic improvement of drought resistance in common bean.

Species with greater seed mass are more tolerant of conspecific neighbours: a key driver of early survival and future abundances in a tropical forest.

Multiple niche-based processes including conspecific negative density dependence (CNDD) determine plant regeneration and community structure. We ask how interspecific and intraspecific density-dependent interactions relate to plant life histories and associated functional traits. Using hierarchical models, we analysed how such interactions affected first-year survival of seedling recruits of 175 species in a tropical forest, and how species abundances and functional traits are related to interspecific variation in density-dependent effects. Conspecific seedling neighbour effects prevailed over the effects of larger conspecific and all heterospecific neighbours. Tolerance of seedling CNDD enhanced recruit survival and subsequent abundance, all of which were greater among larger seeded, slow-growing and well-defended species. Niche differentiation along the growth-survival trade-off and tolerance of seedling CNDD strongly correlated with regeneration success, with manifest consequences for community structure. The ability of larger seeded species to better tolerate CNDD suggests a novel mechanism for CNDD to contribute to seed-size variation and promote species coexistence through a tolerance-fecundity trade-off.

Characteristics of fruits of atemoya cultivars produced in northern Paraná state / Caracterização dos frutos de cultivares de atemóia produzidos no norte do Paraná

The atemoya, Annona squamosa Mill. x A. cherimola L., is a hybrid of the sugar apple and cherimoya. It has been of great interest in Brazil, but there is little information on fruit characteristics. The aim of this research work was to evaluate physical and chemical characteristics of fruits of four atemoya cultivars in the North of Paraná State conditions. Cultivars PR-3, Gefner, Thompson, and African Pride presented fruit weight of 368, 275, 313 and 357 g and flesh percentage of 58, 63, 46 and 51 %, respectively. Seed number per fruit ranged from 23 to 38. Titratable acidity was 0,17 % (in PR-3) to 0,30 % (in Thompson) and total soluble solids were from 16,4 oBrix (in African Pride) to 26,1 oBrix (in Thompson).

A atemóia é um híbrido resultante do cruzamento entre a cherimóia (Annona cherimola Mill.) e a fruta do conde (A. squamosa L.). Sua produção tem tido interesse crescente no Brasil, mas existem poucos dados disponíveis sobre as características dos frutos produzidos. O objetivo do presente trabalho foi determinar características químicas e físicas dos frutos de quatro cultivares de atemóia para as condições do Norte do Paraná. As cultivares PR-3, Gefner, Thompson e African Pride apresentaram peso médio de 368, 275, 313 e 357 g e porcentagem de polpa de 58, 63, 46 e 51 %, respectivamente. O número médio de sementes por fruto variou de 23 a 38. A acidez titulável foi de 0,17 % (para PR-3) a 0,30 % (para Thompson) e o teor de sólidos solúveis foi de 16,4 oBrix (para African Pride) a 26,1 oBrix (para Thompson).

Observations about the insect pollination of soybean (Glycine max) / Observações sobre a polinização entomófila da cultura de soja (Glycine max MERRIL)

The aim of this study was to check the increase of seed production of soybean, cv IAC-14, owing lo the cross pollination performed by insects, mostly honey bees. The honey bee Apis mellifera was very numerous in the area owing to the large number of hives in nearby bee yards. At the flowering time (February, 1994) pollination cages (4mx3mx2m) were set up with the objective of obstructing the insect access. Other areas with the same dimension (4mx3m) remained freely visited by bees and other insects, and still other areas had their plants bagged with gauze. The experimental design used was the complete randomized one with three treatments (caged, visited and bagged plants). The mean of the number of pods per pit, the number of seeds per pod, the number of seeds per pit, the weight of pods per pit and the weight of seeds per pit were compared by the Tukey test (P 0.05). It was verified that the numbers of pods and seeds per pit were bigger (P 0.05) in the visited plants (199.65 and 397.54) than in the caged ones (125.90 and 218.05). On the other hand, the numbers of pods and seeds per pit in the caged plants were bigger than ones of the bagged plants (59.53 and 99.52). The number of seeds per pod in the visited plants was bigger (P 0.05)(1.91) than the ones of the caged plants(1.66). The weights of pods and seeds per pit were bigger (P 0.05) in the visited plants (66.

O trabalho desenvolveu-se com o objetivo de verificar se o cultivar IAC-14 de soja, apresenta possibilidade de aumento de produção devido a polinização cruzada, realizada principalmente por abelhas (Apis mellifera),em uma área onde a concentração de colméias desta espécie é muito alta. Durante o florescimento (fevereiro de 1994) foram instaladas gaiolas de polinização de 4mx3mx2m, que impediam o acesso de insetos; áreas de iguais dimensões (4mx3m) permaneceram livremente visitadas por abelhas e outros insetos e ainda, outras áreas tiveram suas plantas ensacadas com filó. O delineamento experimental utilizado foi o inteiramente ao acaso com 3 tratamentos (gaiolas teladas, áreas visitadas e plantas ensacadas com filó). As médias do número de vagens/cova, número de sementes/vagem, número de sementes/cova, peso de vagens/cova e peso de sementes/cova, foram comparadas pelo teste de Tukey (P 0,05). Verificou-se que os números de vagens e de sementes/cova foram maiores (P 0,05) nas plantas visitadas (199,65 e 397,54) do que nas plantas cobertas com gaiolas teladas (125,90 e 218,05) e estes, por sua vez, foram maiores do que nas plantas ensacadas com filó (59,53 e 99,52). Para o número de sementes/vagem, as plantas visitadas apresentaram média maior (P 0,05)(1,91) do que as plantas cobertas com gaiolas (1,66). Os pesos das vagens e das sementes/cova foram maiores (p 0,05) n

Observations about the insect pollination of soybean (Glycine max) / Observações sobre a polinização entomófila da cultura de soja (Glycine max MERRIL)

The aim of this study was to check the increase of seed production of soybean, cv IAC-14, owing lo the cross pollination performed by insects, mostly honey bees. The honey bee Apis mellifera was very numerous in the area owing to the large number of hives in nearby bee yards. At the flowering time (February, 1994) pollination cages (4mx3mx2m) were set up with the objective of obstructing the insect access. Other areas with the same dimension (4mx3m) remained freely visited by bees and other insects, and still other areas had their plants bagged with gauze. The experimental design used was the complete randomized one with three treatments (caged, visited and bagged plants). The mean of the number of pods per pit, the number of seeds per pod, the number of seeds per pit, the weight of pods per pit and the weight of seeds per pit were compared by the Tukey test (P 0.05). It was verified that the numbers of pods and seeds per pit were bigger (P 0.05) in the visited plants (199.65 and 397.54) than in the caged ones (125.90 and 218.05). On the other hand, the numbers of pods and seeds per pit in the caged plants were bigger than ones of the bagged plants (59.53 and 99.52). The number of seeds per pod in the visited plants was bigger (P 0.05)(1.91) than the ones of the caged plants(1.66). The weights of pods and seeds per pit were bigger (P 0.05) in the visited plants (66.

O trabalho desenvolveu-se com o objetivo de verificar se o cultivar IAC-14 de soja, apresenta possibilidade de aumento de produção devido a polinização cruzada, realizada principalmente por abelhas (Apis mellifera),em uma área onde a concentração de colméias desta espécie é muito alta. Durante o florescimento (fevereiro de 1994) foram instaladas gaiolas de polinização de 4mx3mx2m, que impediam o acesso de insetos; áreas de iguais dimensões (4mx3m) permaneceram livremente visitadas por abelhas e outros insetos e ainda, outras áreas tiveram suas plantas ensacadas com filó. O delineamento experimental utilizado foi o inteiramente ao acaso com 3 tratamentos (gaiolas teladas, áreas visitadas e plantas ensacadas com filó). As médias do número de vagens/cova, número de sementes/vagem, número de sementes/cova, peso de vagens/cova e peso de sementes/cova, foram comparadas pelo teste de Tukey (P 0,05). Verificou-se que os números de vagens e de sementes/cova foram maiores (P 0,05) nas plantas visitadas (199,65 e 397,54) do que nas plantas cobertas com gaiolas teladas (125,90 e 218,05) e estes, por sua vez, foram maiores do que nas plantas ensacadas com filó (59,53 e 99,52). Para o número de sementes/vagem, as plantas visitadas apresentaram média maior (P 0,05)(1,91) do que as plantas cobertas com gaiolas (1,66). Os pesos das vagens e das sementes/cova foram maiores (p 0,05) n