Carlos Eduardo de Oliveira Camargo

Melhoramento do trigo: VI. hereditariedade da tolerância a três concentrações de alumínio em solução nutritiva

No estudo dos cultivares de trigo C-3, BH-1146, Siete Cerros e Brevor em solucoes nutritivas contendo oito concentracoes de aluminio (0, 1, 2, 3, 4, 5, 6 e 10mg/litro), BH-1146 e C-3 mostraram tolerância a todas as concentracoes de Al empregadas, e Brevor e Siete Cerros apresentaram-se sensiveis a presenca de 1mg/litro de Al3+ nas solucoes. A tolerância a dada concentracao de aluminio foi medida pela capacidade de crescimento da raiz primaria central da planta em solucao nutritiva completa, apos um tratamento de 48 horas em solucao contendo determinada quantidade de aluminio. Os cultivares C-3 e Siete Cerros, considerados pais, e as populacoes F1 e F2, provenientes dos seus cruzamentos, foram testados em solucoes nutritivas contendo 3, 6 e 10mg/litro de aluminio. Os resultados obtidos mostraram que, para 3mg/litro de aluminio, o cultivar C-3 diferiu de Siete Cerros por um par de genes dominantes para tolerância. Houve uma quebra gradual da dominância do par de genes responsavel pela reacao de tolerância quando se empregou a concentracao de 6mg/litro de Al3+. O cultivar Siete Cerros diferiu do C-3 por um par de genes dominantes para sensibilidade, quando foram estudados em solucao nutritiva contendo 10mg/litro de Al3+, ou o C-3 diferiu do Siete Cerros por um par de genes dominantes para tolerância, nessa concentracao, considerando que os individuos heterozigotos das populacoes F1 e F2, apresentaram reacao de sensibilidade. Os individuos heterozigotos das populacoes F1 e F2, revelaram tolerância a 3mg/litro, a qual foi diminuida a 6mg/litro, e apresentaram suscetibilidade total a 10mg/litro, com base na hipotese de a tolerância ser devida a um par de genes dominantes. Altos valores da herdabilidade em sentido amplo (0,725 a 0,895) indicaram que a selecao para tolerância ao aluminio seria eficiente na populacao proveniente do cruzamento entre um cultivar tolerante (C-3) e um sensivel (Siete Cerros). Com grandes populacoes F2, seria interessante selecionar as plantas em altas concentracoes de Al3+ (10mg/litro) na solucao, pois seriam eliminadas as sensiveis (homozigotas recessivas e heterozigotas) e selecionadas as tolerantes homozigotas. Por outro lado, seria de interesse utilizar baixas concentracoes de aluminio (3mg/litro) na solucao quando pequenas populacoes F2 forem disponiveis, eliminando somente as plantas sensiveis (homozigotas recessivas) e selecionando as tolerantes (homozigotas e heterozigotas).

Trigo duro: tolerância à toxicidade do alumínio em soluções nutritivas e no solo

Twenty three durum wheat inbred lines, one triticale and six bread wheat cultivars were studied in aerated nutrient solutions for aluminum tolerance with six different levels of aluminum (0, 1, 2, 3,4 and 6 mg/I), under constant temperature, 25 ± 1°C and pH 4.0. Aluminum tolerance was evaluated by measuring the root growth in an aluminum-free complete nutrient solution after a treatment of 48 hours in an aluminum solution. All duram wheat lines and Siete Cerros and Anahuac bread wheat cultivars were sensitive to 1 mg/l of Al3+. The bread wheat Alondra-S-46 was sensitive to 4 mg/l of A]3+ The triticale Chiva and the bread wheats BH-1146, IAC-24 and IAC-60 exhibited tolerance to 6 mg/l of Al3+. The same genotypes were also studied in trials carried out in the field using acid and limed soils. The durum wheat lines presented low grain yield (939-2,243 kg(ha) and the triticale and bread wheat cultivars, tolerant to Al toxicity, showed high grain yield (3,584-4,922 kg/ha) in acid soil. The best durum wheat line produced 4,128 kg/ha and the best triticale and bread wheat cultivars produced 4,547 and 4,906 kg/ha, respectively, in limed soil. These results confirmed that incorporation of aluminum tolerance into the durum wheat germplasm is needed in order to permit its growth in acid soils.

Avaliação de genótipos de triticale e trigo em ambientes favoráveis e desfavoráveis no Estado de São Paulo

The environment adaptation of eighteen triticale and two wheat genotypes were evaluated in experiments carried out at two different sites of the Mococa Agronomy Experimental Station, Sao Paulo State, Brazil, in the period 1996-99. The favorable environment was provided with sprinkler irrigation on an upland; the unfavorable condition consisted of a moist flat area with basin irrigation system. The environment diversity induced different genotypes response patterns. Under the sprinkler irrigation system the yields were higher for both species, but the triticale genotype TATU 4/ARDI 1 presented the highest grain yield. Under moist and flat area condition the triticale LT 978.82/ASAD//TARASCA showed the highest yield. The wheat genotype IAC 60 showed large variations in grain yield in the moist flat area over the two cropping years. The plant cycle from emergence to heading showed higher variation among the triticale genotypes under moist low and flat area in comparison with the upland sprinkler irrigation condition. The results suggested the wheat genotypes presented a specific adaptation for upland with sprinkler irrigation environment and the triticale group of genotypes presented a broader adaptation.

Adaptabilidade e estabilidade de linhagens de trigo no Estado de São Paulo

Adaptability and Stability parameters were estimated by two non-parametric methodologies for grain yield in 20 wheat genotypes, 18 Mexican inbred lines and two cultivars, which were evaluated in three locations of Sao Paulo State, during 2001 and 2002. Significant effects were observed for genotypes, years and locations, indicating that the performance of the inbred lines was not coincident for the two years and the three locations. Genotypes x locations, years x locations and genotypes x years x locations interactions were significant. Independently of the methodology and considering the analysis for the two years and for the three locations, inbred lines 13 (HAHN/2*WEAVER) and 3 (SERI M 82) ranked among the five, with wide adaptability and stability. These inbred lines, specially the 13, could be recommended for cultivation by growers after the evaluation of other interesting agronomic traits, such as plant height, disease resistance and aluminum tolerance. The two methodologies provided similar results with easy estimates and interpretation.

Produtividade e resposta de genótipos de trigo ao nitrogênio

This study was based on the hypothesis of existence of genetic variability among genotypes of wheat (Triticum aestivum L.) in relation to the nitrogen utilization and response to application of this nutrient. The experiments were carried out at the Campinas and Tatui Experiment Stations, Instituto Agronomico, State of Sao Paulo, Brazil, under sprinkler irrigation conditions, in succession to fallow (Campinas) and rice or lablab crops (Tatui), during 1987-1991 years. It was used a randomized complete block design in a split plot arrangement with four replications. The main plots were the levels of nitrogen (0, 60 and 120 kg/ha) and the split-plots were the wheat genotypes: BH-1146, IAC-5, IAC-24, IAC-25, IAC-60, IAC-161, IAC-162 and Anahuac. The results showed that in relation to the grain yield, the most productive genotypes were IAC-60, IAC-161 and IAC-162 which responded up to 120 kg/ha of applied nitrogen and the remaining responded only to 60 kg/ha of N, in Campinas during 1991. At the Tatui Experiment Station, in 1987, the most productive genotypes were IAC-60 and IAC-24 and all genotypes responded up to 120 kg/ha of applied nitrogen; but they did not respond to the high levels of applied nitrogen, during the years 1988 to 1990, in succession to lablab crops.

Iguaçu (IAC-21) e Araguaia (IAC -22): cultivares de trigo de sequeiro para o Estado de São Paulo

Two new selected germoplasms of wheat (Iguacu and Araguaia) were tested against two commercial varieties (BH-1146 and IAC-5) for yield and resistance to stem and leaf rusts in several experiments carried out in different locations of the wheat areas of the State of Sao Paulo, Brazil, in the period 1978-1982. Cultivar Iguacu produced 8% and 12% more grain per hectare in comparison with respectively, cultivars BH-1146 and IAC-5; cultivar Araguaia had, respectively, 5% and 14% more grain yield than the same commercial varieties. Iguacu and Araguaia cultivars presented less stem rust infection than BH-1146 and IAC-5 while Araguaia had a lower infection level than Iguacu under field conditions. It was not observed differences in resistance to leaf rust among them. Araguaia exhibited better bread qualities than Iguacu but both showed better qualities than the used commercial wheat flour.

Efeito da temperatura da solução nutritiva na tolerância ao alumínio de cultivares de trigo

The aluminum tolerance of eight wheat cultivars was studied in nutrient solutions using four different levels of this element combined with four different temperatures. The tolerance was evaluated by measuring, the root growth in an aluminum-free complete nutrient solution after a previous treatment with Al using 0; 0.5; 1.0 and 6.0mg/litro at temperatures of 22°C ± 1°C, 26°C ± 1°C, 30°C ± 1°C and 34°C ± 1°C. The wheat cultivars BH-1146, IAC-5 and IAC-21 were the most tolerant, IAC-17, Alondra-S-46 and Sonora-64 showed moderate tolerance, Tobari-66 was moderately sensitive and Siete Cerros was sensitive to the presence of increasing concentrations of Al3+ in the treatment solution under a constant temperature. The aluminum toxicity symptom (inhibition of root growth) was dependent on the temperature and the amount of aluminum added to the treatment solutions. For the same level of Al3+, the Al toxicity symptoms increased when the temperature increased in the treatment solution, for all the cultivars studied. Apparently wheat tolerance to Al3+ is a relative rather than absolute characteristic, depending on temperature among other characteristics.

Comportamento agronômico de linhagens de trigo no Estado de São Paulo

Eighteen wheat lines and the check cultivars IAC-24 and IAC-289 were evaluated in six trials carried out at different locations under dryland and sprinkler irrigation conditions, for grain yield, agronomic characteristics and disease resistance. In laboratory conditions, the germplasms were evaluated for their Al toxicity tolerance in nutrient solutions. The line L9 and the cultivar IAC-289 were superior in grain yield, considering the average of the six trials. The line L8 exhibited short stature associated to lodging resistance and early maturity. In relation to leaf rust the lines L1, L17 and L20 were resistant. All genotypes were susceptible to the causal agents of leaf spot and mildew. The line L7, showed long heads with the highest number of spikelets; IAC-289 and L17, the largest number of grain per head and per spikelet, respectively; and L11, the heaviest grains. All evaluated genotypes were tolerant to Al3+ toxicity, excepting the control cultivar Anahuac and the lines L15 and L20, which exhibited high sensibility.

Tolerância de cultivares de trigo, triticale e centeio em diferentes níveis de alumínio em solução nutritiva

Seven bread wheat (Triticum aestivum L.) cultivars, one durum wheat (Triticum durum L.) cultivar, seven triticale cultivars and two rye cultivars (Secale cereale L.) were studied to aluminum toxicity using four different levels of this element in nutrient solutions at constant temperature (28 °C ± 1 °C). The tolerance was measured taking into account the root growth in an aluminum-free complete nutrient solution after a previous Al3+ treatment. With a toxic concentration of aluminum, the primary roots did not grow at all and remained thickned at the tip as a typical aluminum injury. The rye cultivars: Goyarowo and Branco were tolerant to 20 ppm of Al3+; the bread wheat cultivars Siete Cerros and Tobari and the durum wheat Cocorit were sensitive to 5 ppm of Al3+, BH-1146. IAC-5, BR-1 and IAC-18 were tolerant while the cultivar IAC-17 showed moderate tolerance to 5 ppm of Al3+; the triticale cultivars, PET-763, TCEP-77142, PFT-764, TCEP-77138, TCEP-77136, TCEP-75709 and Cynamon were tolerant to 5 ppm of Al3+. All wheat and triticale cultivars were very sensitive to 10 ppm of Al3+. These results showed the possibility to grow rye as an optional culture during the winter time, under acid soils with high aluminum, in the State of Sao Paulo, Brazil.

Melhoramento do trigo: X. Estimativas da herdabilidade e correlações entre tolerância à toxicidade de alumínio e produção de grãos com outros caracteres agronômicos em trigo

High grain yield potential, and Al sensitive cultivar Alondra S-46 was crossed with standard height, low grain yield potential, Al tolerant cultivars IAC-5, BH-1146 and C-3. Parents, F1s, F2s and reciprocal backcrosses were tested for their seedling reaction to 6 ppm of Al3+ in nutrient solution. Grain yield, plant height, number of spikes per plant, number of spikelets per spike, number of grains per spike, number of grains per spikelet, 100-grain-weight and spike length were determined for the same populations at maturity. Narrow sense heritability estimates were high for spike length, number of grains per spike, 100-grain-weight, and plant height; moderate for number of spikes per plant and number of spikelets per spike; and low for the rest of the agronomic characteristics under study. Additive effects were the main source of genetic variation for spike length, plant height, number of grains per spike and 100-grain-weight. Grain yield of the studied populations was significantly correlated with all the agronomic characteristics under study except the number of spikelets per spike. Tolerance to Al3+ toxicity was not associated with plant height (except for the population from the cross Alondra S-46 x IAC-5), grain yield and number of grains per spikelet (spike fertility). The results suggested that there is a possibility of selecting plant types that combine Al3+ tolerance, semi-dwarf height levels and high yield potential, to be grown on acid soils