Selection Indices For Improvement Research Articles

Association pattern among the yield attributes in varieties and hybrids of sunflower (Helianthus annuus L.)

SUMMARY Three varieties, CO 4, Morden and TNHSF 239 (a pre-release culture) and two hybrids, TCSH 1 and KBSH 44, were selected for this study. Simple correlation coefficients were estimated among characters for individual varieties and hybrids. Two traits, seed yield and 100-seed weight, are important selection indices for oil yield improvement in both varieties and hybrids. Head weight can be considered as a selection index for improvement of seed and oil yield in hybrids only. Likewise, oil content is an important selection index for oil yield improvement in varieties. It can also be inferred that the results obtained from the association analysis of pooled data for varieties and hybrids will give ambiguous results and have a negative impact on the yield improvement program. Thus it is desirable to compute separate association analyses for each variety and hybrid to identify effective selection indices for the improvement of sunflower. RESUMEN Se seleccionaron para este estudio tres variedades llamadas CO 4, Morden, TNHSF 239 (variedad precomercial) y dos híbridos TCSH 1 y KBSH 44. Se estimaron coeficientes de correlación simples entre caracteres para cada variedad e híbrido separadamente. Los atributos rendimiento de semilla y peso de 100 semillas son importantes índices de selección para el mejoramiento del rendimiento de aceite tanto para variedades como híbridos. El peso del tálamo puede considerarse un índice de selección para el mejoramiento del rendimiento en semilla y aceite sólo en el caso de los híbridos. De manera similar, el contenido de aceite es un índice de selección importante para la mejora del rendimiento de aceite sólo en el caso de las variedades. Puede también inferirse que los resultados obtenidos de los análisis de asociación de datos en variedades e híbridos analizados en conjunto producirán resultados ambiguos y tendrían un impacto adverso en un programa de mejoramiento por rendimiento. Por lo tanto, siempre es deseable conducir análisis de asociación separados para cada variedad o híbrido para identificar índices de selección para el mejoramiento de girasol. RÉSUMÉ Les trois variétés CO 4, Morden, TNHSF 239 (cultivar experimental) et les deux hybrides TCSH 1 et KBSH 44 ont été sélectionnés pour cette étude. Les coefficients de corrélation simple entre caractères ont été estimés séparément pour chaque variété ou hybride. La production de grains et le poids de 100 grains sont des indices de sélection importants pour l’amélioration du rendement en huile pour les variéts comme pour les hybrides. Le poids du capitule peut être considéré comme un index de sélection important pour le rendement en grain et en huile seulement pour les hybrides. De la même façon, la teneur en huile est un index de sélection important pour l’amélioration du rendement en huile seulement pour les variétés. Il peut également être inféré que les résultats obtenus en agrégeant les données des variétés et des hybrides aurait conduit à des conclusions ambiguës et aurait eu des effets néfastes sur le programme d’amélioration de la productivité. Ainsi il apparaît souhaitable, pour identifier des index de sélection pour l’amélioration du tournesol, de calculer séparément les corrélations entre caractères pour chaque variété et hybride.

Neuromuscular blocking activity and therapeutic potential of mixed-tetrahydroisoquinolinium halofumarates and halosuccinates in rhesus monkeys.

Structure-activity relationships in rhesus monkeys for a novel mixed-onium class of ultra-short-acting nondepolarizing tetrahydroisoquinolinium neuromuscular blockers (NMBs) are described. Bis-onium chlorofumarate 20a with (1R,2S)-benzyltetrahydroisoquinolinium groups was a potent lead compound (ED(95) = 0.079 mg/kg) with an ultra-short duration of NMB effect (7.1 min) and a selectivity index (SI: defined as a ratio of the cardiovascular threshold dose to the ED(95)) similar to that of mivacurium (3). The mean threshold dose for cardiovascular effects with 20a was ca. 20 times its ED(95) value (SI = 20). A novel mixed-onium analogue of 20a was prepared by replacing the benzyltetrahydroisoquinolinium group distal to the fumarate chlorine atom with a (1S,2R)-phenyltetrahydroisoquinolinium moiety. The resulting mixed-onium chlorofumarate 24a displayed good NMB potency (ED(95) = 0.063 mg/kg), ultra-short duration of action (5.6 min) and an improved selectivity index (SI = 57). Several other mixed-onium derivatives containing octanedioate (25a; ED(95) = 0.103 mg/kg), difluorosuccinate (27c; ED(95) = 0.056 mg/kg), and fluorofumarate (28a; ED(95) = 0.137 mg/kg) linkers were also potent, ultra-short-acting NMBs with good to excellent selectivity index values (SI = 37-96). Octanedioate 25a was longer acting at higher doses compared to difluorosuccinate 27c and chlorofumarate 24a. Durations of NMB effect following a 0.4 mg/kg bolus dose (100% block) of 25a, 27c, and 24a were 16.9, 13.0, and 10.0 min, respectively. Recovery time for mixed-onium chlorofumarate 24a following a 1 h continuous infusion at 10-20 microg/kg/min (95-100% block) was ca. 5 min which is similar to that observed following a 0.2 mg/kg bolus dose of this compound and indicates a lack of cummulative effects. Preliminary studies with chlorofumarate 24a in whole human blood revealed that mixed-onium thiazolidine 29 was the major metabolite and that plasma cholinesterases do not play the primary role in duration of NMB effect. The NMB properties of 24a in rhesus monkeys led to its clinical evaluation as a possible alternative to succinylcholine.

IgA nephropathy: effects of clinical indices, ACEI/ATRA therapy and ACE gene polymorphism on disease progression

SUMMARY: In 1985 the authors studied 151 patients with biopsy‐proven IgA nephropathy (IgAN). After a mean follow‐up period of 5 years, 84% had stable renal function, 5% had renal impairment and 11% progressed to end‐stage renal failure (ESRF). The unfavourable prognostic indices were proteinuria > 1 g/day, hypertension, crescents on renal biopsy, glomerulosclerosis and medial hyperplasia of blood vessels. The cumulative renal survival was 89% at 5 years. Fifteen years later, in 2000, with data from the Singapore Renal Registry it was ascertained that 53 patients (35%) had developed ESRF. Using multivariate analysis by the regression model of Cox it was found that serum creatinine, protein selectivity, segmental glomerulosclerosis, crescents and medial hyperplasia were significant predictors of progression. It is also shown that the presence of low‐molecular‐weight (LMW) proteinuria is another index of poor prognosis. Cumulative renal survival of the 151 patients was 65% at 20 years. In a recent study, the response of patients with IgAN to angiotensin‐converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) therapy was examined. There were 21 patients in the treatment group and 20 as controls. After 13 ± 5 months of treatment, 10 responders had improved selectivity index (SI; from 0.26 ± 0.07 to 0.18 ± 0.07, P < 0.001), indicating a shift towards selective proteinuria. This was associated with improvement in serum creatinine from a mean of 1.7 ± 0.6 to 1.5 0.6 mg/dL (P < 0.02) and a decrease in proteinuria from a mean of 2.3 ± 1.1 g/day to 0.7 ± 0.5 g/day (P < 0.001). Eight out of 21 patients in the treatment group who had documented renal impairment had improvement in their renal function, three of whom had normalized renal function. The angiotensin‐converting enzyme insertion/deletion (ACE I/D) polymorphism gene was also genotyped in 100 patients with IgAN (32 of whom were in ESRF) and in 90 normal adult subjects. All DD cases were subjected to confirmation with a second polymerase chain reaction (PCR), performed with the insert‐specific forward primer. Similar genotype frequencies were obtained for the 90 normal control subjects (II: 47%, ID: 44%, DD: 9%); for the 68 patients not in ESRF (II: 47%, ID: 46%, DD: 7%) and for the 32 patients with ESRF (II: 53%, ID: 38%, DD: 9%). The genotype frequencies in all three series are in Hardy–Weinberg equilibrium. These results suggest that ACE I/D polymorphism is not a risk factor for IgAN and is not a predictor for its progression. In conclusion the predictors in the progression of IgAN include abnormal renal function at presentation, segmental glomerulosclerosis, crescents, medial hyperplasia of blood vessels, non‐selective proteinuria, LMW proteinuria and failure to respond to antiproteinuria therapy with ACEI/ATRA. However, the D‐allele of ACE gene polymorphism is not a risk factor.

IgA nephropathy: effects of clinical indices, ACEI/ATRA therapy and ACE gene polymorphism on disease progression

SUMMARY: In 1985 the authors studied 151 patients with biopsy‐proven IgA nephropathy (IgAN). After a mean follow‐up period of 5 years, 84% had stable renal function, 5% had renal impairment and 11% progressed to end‐stage renal failure (ESRF). the unfavourable prognostic indices were proteinuria > 1 g/day, hypertension, crescents on renal biopsy, glomerulosclerosis and medial hyperplasia of blood vessels. the cumulative renal survival was 89% at 5 years. Fifteen years later, in 2000, with data from the Singapore Renal Registry it was ascertained that 53 patients (35%) had developed ESRF. Using multivariate analysis by the regression model of Cox it was found that serum creatinine, protein selectivity, segmental glomerulosclerosis, crescents and medial hyperplasia were significant predictors of progression. It is also shown that the presence of low‐molecular‐weight (LMW) proteinuria is another index of poor prognosis. Cumulative renal survival of the 151 patients was 65% at 20 years. In a recent study, the response of patients with IgAN to angiotensin‐converting enzyme inhibitor/angiotensin receptor antagonist (ACEI/ATRA) therapy was examined. There were 21 patients in the treatment group and 20 as controls. After 13 ± 5 months of treatment, 10 responders had improved selectivity index (SI; from 0.26 ± 0.07 to 0.18 ± 0.07, P< 0.001), indicating a shift towards selective proteinuria. This was associated with improvement in serum creatinine from a mean of 1.7 ± 0.6 to 1.5 ± 0.6 mg/dL (P< 0.02) and a decrease in proteinuria from a mean of 2.3 ± 1.1 g/day to 0.7 ± 0.5 g/day (P< 0.001). Eight out of 21 patients in the treatment group who had documented renal impairment had improvement in their renal function, three of whom had normalized renal function. the angiotensin‐converting enzyme insertion/deletion (ACE I/D) polymorphism gene was also genotyped in 100 patients with IgAN (32 of whom were in ESRF) and in 90 normal adult subjects. All DD cases were subjected to confirmation with a second polymerase chain reaction (PCR), performed with the insertspecific forward primer. Similar genotype frequencies were obtained for the 90 normal control subjects (II: 47%, ID: 44%, DD: 9%); for the 68 patients not in ESRF (II: 47%, ID: 46%, DD: 7%) and for the 32 patients with ESRF (II: 53%, ID: 38%, DD: 9%). the genotype frequencies in all three series are in Hardy‐Weinberg equilibrium. These results suggest that ACE I/D polymorphism is not a risk factor for IgAN and is not a predictor for its progression. In conclusion the predictors in the progression of IgAN include abnormal renal function at presentation, segmental glomerulosclerosis, crescents, medial hyperplasia of blood vessels, non‐selective proteinuria, LMW proteinuria and failure to respond to antiproteinuria therapy with ACEI/ATRA. However, the D‐allele of ACE gene polymorphism is not a risk factor.

Efficiency of one- and two-stage selection indexes for improvement of net economic merit in White Leghorns

The effects of varying intensities of selection at first and second stages, for a given final intensity, on the efficiency of two-stage index selection are described. Data collected on four White Leghorn strains for part and residual egg number, body weights at 20 and 40 weeks and egg weight at 39 to 40 weeks were utilised. Four of the five traits were used in the first stage and all five traits were used in the second stage for the construction of two-stage selection indexes. The index that utilised all five traits had the maximum efficiency for one-stage selection. The relative efficiency of the two-stage index increased with increase in proportion selected at the first stage. A practical breeding schedule that adds the advantage of reduced generation interval by utilising a two-stage index selection is suggested for egg type chickens.

Studies on a selection index for improvement of litter weight in sheep

ABSTRACTThe value of a selection index for 8-week litter weight as a trait of the ewe, combining information on the ewe and on five classes of female relatives, was considered. Adding records on the dam and on paternal half sibs to those of the ewe gives increases of 10 to 50% in the rates of genetic response. The index can be simplified with little loss in efficiency by weighting all records equally for relatives with 1, 2 or more records within each class of relative. In selecting breeding replacements, information on the parents of the sire of the individual being selected may increase the rates of response by a further 20 to 30 %.

Application of Restricted Selection Indexes for Improvement of Economic Value in Oats1

The dollar return from growing oats Avena sativa L. in the midwestern United States is a function of both grain and straw yields. Restricted selection indexes were used to determine the effect of restricting heading date and height on selection potential for economic value among F9‐derived lines from a bulk populatiou of oats. Four unrestricted and eight restricted selection methods were considered. The eight restricted methods comprised two economic values, optimum and base methods, and two degrees of restriction on heading date and height. Expected and actual advances were calculated.Direct selection for increased economic value saved lines with late heading dates and tall plants. Holding heading date and height to the means of the unselected population removed correlated responses in heading date and height, but decreased advance from selection for economic value. More severe restrictions on heading date and height reduced the advance in economic value to near 0.0. Restrictions on heading date and height had a more severe effect on straw yield than on grain yield.Optimum restricted selection indexes, in which grain and straw yields were entered as separate traits, were only slightly more efficient than base restricted indexes in which the two traits were combined into the single character economic value.Changing the relative economic values of grain and straw had little effect on expected or actual advances. Restricted selection for economic value was effective with measurements on plant weight, heading date, and height only; i.e., without measuring grain yield.Expected and actual advances for heading date and height agreed closely for all methods. Expected advances for grain yield, straw yield, and economic value were overestimates of actual advances with unrestricted methods, but agreed closely with actual advances for restricted methods.

Relationship of Leaf Photosynthesis to Forage Yield of Tall Fescue1

Genetic variation exists for leaf photosynthesis in tall rescue (Festuca arundinacea, Schreb.), but little information exists on its relationship to forage yield. Therefore, net carbon exchange (NCE) of leaves of tall rescue genotypes was measured in the field during regrowth stages and compared to forage yield of the swards in the subsequeut harvest. Genetic variation existed for both yield and NCE on a leaf area basis, but no consistent relationship between these characters was found. Both NCE and forage yield were increased by irrigation during drought. Correlations between NCE and yield also tended to change from positive to negative with irrigation. Although NCE on a single leaf basis is a primary component of forage yield, other factors such as a environmental stress, canopy shape, and dry matter distribution will need to be considered if NCE is to be included in an effective selection index for improvement of forage yield.