Redução populacional de trigo no rendimento e na qualidade fisiológica das sementes

Abstract

RESUMO -Na produção de sementes de trigo diversos fatores (bióticos e abióticos) podem alterar o rendimento e a qualidade de sementes, dentre esses cita-se o estabelecimento adequado das plantas no campo. Dessa forma, objetivouse com esse trabalho verificar o efeito da redução da população de trigo de forma aleatória no rendimento e na qualidade fisiológica das sementes produzidas. O estudo foi realizado nas cultivares Horizonte, Marfim, Mirante e Quartzo. Anteriormente à fase do afilhamento, procedeu-se a retirada de plantas de maneira aleatória nas intensidades de 0; 20; 40 e 60% em relação à população original (350 plantas por metro quadrado). Após a colheita, avaliou-se o rendimento e a qualidade das sementes produzidas, por meio dos testes de germinação, envelhecimento acelerado, condutividade elétrica massal e massa de mil sementes. Verificou-se que as cultivares apresentam desempenho diferente quando submetidas a reduções aleatórias de plantas demonstrando capacidades distintas em compensar eventuais falhas na semeadura. A resposta para rendimento de trigo em função da redução aleatória na população de plantas varia conforme o genótipo utilizado. Quanto à qualidade das sementes produzidas, reduções aleatória de plantas de trigo afetam negativamente a qualidade fisiológica das sementes. Palavras-chave:Triticum aestivum L. Sementes-rendimento. Germinação.ABSTRACT -In the production of wheat seeds several factors (both biotic and abiotic) can alter the yield and quality of the seeds, among these is the appropriate establishment of the plants in the field. The aim of this work therefore, was to investigate the effect of randomly reducing the wheat population on yield and physiological quality of the seeds produced. The study was carried out on the cultivars, Fundacep Horizonte, Marfim, Mirante and Quartzo. Prior to the tillering stage, plants were removed at random at levels of 0; 20; 40 and 60% of the original population (350 plants per square metre). After harvest, the yield and quality of the seeds produced were evaluated by testing germination, accelerated ageing, mass electrical conductivity and thousand-seed weight. It was found that the cultivars perform differently when subjected to random plant reduction, demonstrating different capabilities in compensating for any flaw in seeding. The response for wheat yield due to the random reduction in plant population varies by genotype. As for the quality of the seeds produced, random reductions of wheat plants negatively affect the physiological quality of the seeds.

Seedling emergence and yield performance of wheat cultivars depending on seed vigor and sowing density

“…Plants originated by low vigor seeds presented a higher number of tillers per plant, in relation to the plants coming from high vigor seeds (Table 4); this may be due to the lower plant density established under these conditions. According to Caires et al (2001) and Barbieri et al (2013), accentuated reductions in the wheat plant population lead to a greater need for compensation through the emission of tillers, since in this situation there is less intraspecies competition for factors from the medium, such as water, light and nutrients. However, under this condition, it is necessary to have proper environmental conditions helping tillering, as well as the formation of effective tillers.…”

Treatment with fungicides and insecticides on the physiological quality and health of wheat seeds

“…Nevertheless, around 50% of the wheat consumed within Brazil is imported (CONAB, 2014). Thus, there is great socioeconomic interest in the country in increasing its production so as to meet domestic demand and because of the benefits generated from growing it (Barbieri et al, 2013).…”

Physiological quality and aflatoxin presence in wheat seeds treated with fungicides and adjuvants during crop development

“…It can be observed that the treatments 2 (Nativo + adjuvant Aureo) and 14 (Priori Xtra + adjuvant Nimbus with 0:25 + 0:15% dose) showed the highest seed mass, and different adjusted mass values, which means that the increasing moisture was responsible for the mass increase in treatment 14. Barbieri et al (2013) found out that smaller size or smaller seed mass may have lower physiological quality. However, Avila et al (2005) studied canola seed, and observed no relationship between mass of a thousand seeds and vigor.…”

“…In Brazil, wheat yield increase has an economic interest, because in addition to meeting the demand, its cropping improves soil conditions and provides waste for summer crops, such as soybeans and maize (BARBIERI et al, 2013).…”