Allelic variation at the Vrn-A1, Vrn-B1, Vrn-D1, Vrn-B3 and Ppd-D1a loci of Pakistani spring wheat cultivars

Flowering time in bread wheat (Triticum aestivum L.) is controlled by vernalization and photoperiod response, and earliness per se genes. The genetic basis of flowering time has not been investigated in Pakistani bread wheat. This study was, therefore, conducted to determine the allelic composition at Vrn-A1, Vrn-B1, Vrn-D1, Vrn-B3 and Ppd-D1a loci of 59 Pakistani spring bread wheat cultivars. These cultivars, along with 4 isogenic lines for vernalization genes were characterized with previously reported DNA markers designed for detecting allelic variation at 4 Vrn (Vernalization) and 1 Ppd (Photoperiod) loci. Spring habit Vrn-A1a allele was found in 36 percent cultivars either alone or with spring habit Vrn-B1 and Vrn-D1 alleles. Two wheat cultivars had the dominant Vrn-A1c allele, whereas none of the cultivars had Vrn-A1b. Spring habit Vrn-B1 was the most frequent allele (64 percent) present either alone or with Vrn-A1a, Vrn-A1c and Vrn-D1. Spring habit Vrn-D1 was found in 61 percent cultivars. Vrn-D1 was singly found in 25 percent cultivars and along with Vrn-B1 in 29 percent cultivars. Dominant Vrn-B3 was absent in all cultivars studied. All cultivars except Era had the photoperiod insensitive allele Ppd-D1a. We did not find any association between the flowering time and Vrn allelic composition of the studied cultivars. This indicated that the partial vernalization requirement of cultivars with Vrn-B1 and Vrn-D1 alleles is probably fulfilled during Pakistani growing season. Earliness per se and the photoperiod sensitive loci other than Ppd-D1 need to be investigated to further understand the genetic basis of flowering time in Pakistani wheat.

Conception rate in Holstein cows treated with GnRH or hCG on the fifth day post artificial insemination during summer / Taxa de concepção de vacas Holandesas tratadas com GnRH ou hCG no quinto dia após a inseminação artificial no verão

Lactating Holstein cows (n=158), at 213±112 days in milking and averaging 26±9kg of milk per day, were randomly assigned to one of three treatment groups: control (CG, n=52, saline), GnRH (GG, n=55, 100g gonadorelin), and hCG (HG, n=51, 2500IU) given five days after artificial insemination (AI). Rectal temperature was taken at the moment of AI and blood samples were collected five, seven, and 12 days after AI. Pregnancy was determined between 42 and 49 days after AI. Concentration of progesterone (P4) in serum (ng/ml, mean±SE) for CG, GG, and HG were, respectively, 2.7±0.4, 2.5±0.4, and 3.2±0.5 on day 5; 4.8±0.4, 4.2±0.4, and 5.7±0.5 on day 7; and 5.2±0.4, 6.9±0.4, and 8.5±0.5 on day 12 after AI. P4 concentration had proportional increase in serum between days 5 and 7 after AI (CG: 178 percent, GG: 168 percent, and HG: 178 percent), suggesting that the treatments did not induce a luteotropic effect on the existing corpus luteum (CL). Concentrations of P4 increased between days 7 and 12 in cows treated with GnRH and hCG (GG: 164 percent, and HG: 149 percent, P<0.01); but not in control cows (GC: 18 percent, P=0.31), suggesting that a new CL was formed. Treatments with GnRH or hCG increased conception rates in cows with rectal temperature below 39.7ºC (CG: 10.1 percent, n=26, GG: 36.8 percent, n=27; and HG: 32.8 percent, n=21), but not in cows with rectal temperature above 39.7ºC (CG: 15.2 percent, n=26; GG: 17.8 percent, n=28; and HG: 24.4 percent, n=30). These data suggest that high body temperature masked the positive impact of treatment with GnRH or hCG on day 5 after AI on conception.

Vacas da raça Holandesas em lactação (n=158) aos 213±112 dias de lactação e produção de 26±9kg leite/dia, foram aleatoriamente distribuídas em três grupos: controle (GC, n=52, salina); GnRH (GG, n=55, 100mcg de gonadorelina); e hCG (GH, n=51, 2500UI de hCG) aplicado no dia 5 após a inseminação artificial (IA). A temperatura retal foi verificada no momento da IA, e as amostras de sangue coletadas nos dias 5, 7 e 12 após a IA. A concepção foi determinada entre os dias 42 e 49 após IA. As concentrações séricas de progesterona (P4 - ng/ml, média±EPM) para GC, GG, e GH foram, respectivamente: no dia 5: 2,7±0,4, 2,5±0,4 e 3,2±0,4; no dia 7: 4,8±0,4, 4,2±0,4 e 5,7±0,5; e no dia 12 após a IA: 5,2±0,4, 6,9±0,4 e 8,5±0,5. O aumento proporcional na concentração sérica de P4 entre os dias 5 e 7 após IA (GC: 178 por cento, GG: 168 por cento, e GH: 178 por cento) sugere que os tratamentos não induziram efeito luteotrópico no corpo lúteo (CL) existente. O aumento na P4 sérica entre os dias 7 e 12 nos animais tratados com GnRH ou hCG (GG: 164 por cento e GH: 149 por cento, P<0,01) em relação aos animais controle (GC: 18 por cento, P=0,31), sugere a indução de novo CL. Os tratamentos com GnRH ou hCG aumentaram as taxas de concepção nas vacas com temperatura retal abaixo de 39,7ºC (GC: 10,1 por cento, n=26; GG: 36,8 por cento, n=27 e GH: 32,8 por cento, n=21), mas não em vacas com temperatura retal acima de 39,7ºC (15,2 por cento n=26; 17,8 por cento, n=28 e 24,4 por cento, n=30). Os resultados sugerem que a alta temperatura corporal pode mascarar os efeitos positivos do tratamento com GnRH ou hCG no dia 5 após a IA, na concepção.