Differences in early growth of shoots and roots in potato clones

Summary Genetic differences have been found between potatoclones in early growth of shoots, early growth of roots and in the roots/shoots ratio. The early growth of shoots was positively correlated with the early growth of roots both in the variation of individual plants within a clone and in the variation of individual clones. Clones with greater early shoot growth exhibited earlier tuber growth and had a shorter growing period. Clones with a higher roots/shoots ratio exhibited delayed tuber formation and a longer growing period. The possibility of applying these results to the selection of high-yielding clones is discussed.

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Zusammenfassung In 25 Kartoffelklonen, die auf leichten, trockenen B?den vergleichsweise gute Ertr?ge brachten, wurde 1975 und 1976 das frühe Wachstum gemessen. In jedem Jahr wurden bei 4 Pflanzen pro Klon an drei Ernteterminen folgende Messungen durchgeführt: Gewicht der Stengel. Gewicht der Wurzeln und das Verh?ltnis Wurzel: Stengel. Die selben Klone wurden zwei Jahre in Feldversuchen auf leichten, trokkenen B?den geprüft. In den Kartoffelklonen wurden genetische Unterschiede in Bezug auf das frühe Wachstum der Stengel, der Wurzeln und das Verh?ltnis Wurzel: Stengel gefunden (Tabelle 1). Das frühe Wachstum der Stengel war mit dem frühen Wachstum der Wurzeln positiv korreliert, sowohl in der Variation zwischen Einzelpflanzen des Klons als auch Zwischen den Klonen (Tabelle 2, Fig. 1). Bei Klonen mit einem st?rkeren frühen Wachstum der Stengel setzte die Knollenbildung früher ein und die Wachstumszeit war kürzer. Klone mit einem h?heren Verh?ltnis Wurzeln: Stengel zeigten eine verz?gerte Knollenbildung und eine l?ngere Wachstumszeit (Tabelle 3). Burton (1966) und Raeuber & Engel (1963) weisen daraufhin, dass hoch ertragsreiche Kartoffeln eine schnelle Entwicklung verbunden mit einem verl?ngerten Wachstum besitzten sollten. Die gezeigten Ergebnisse deuten an, dass die erw?hnten Kennzeichen auf einfache Weise im frühen Wachstum von Kartoffelklonen bestimmt werden k?nnen: grosses G ewicht der Stengel zeigt eine schnelle Entwicklung an und ein grosses Verh?ltnis Wurzeln: Stengel ein verl?ngertes Wachstum. In Versuchsmaterial wurden 2 Klone gefunden, in denen ein h?heres Gewicht der Stengel mit einem gr?sseren Verh?ltnis Wurzeln: Stengel (Fig. 1) kombiniert ist. Die m?gliche Bedeutung dieser Ergebnisse für die Züchtung hoch ertragsreicher Kartoffeln wird diskutiert.

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Résumé Dans 25 clones produisant bien en sols légers et déficients en eau, la croissance en début de végétation a été mesuré en 1975 et 1976. Chaque année, pour chaque clone, à trois dates de récolte, les mesures suivantes ont été effectuées sur 4 plantes: poids des pousses, poids des racines et rapport racines/pousses. Les mêmes clones ont aussi été testés pendant deux ans au champ, en sols légers et déficients en eau. Des différences génétiques ont été trouvées entre clones au niveau de la croissance des pousses, des racines, du rapport racines/pousses (tableau 1). Des corrélations positives intraclones et interclones entre croissance des pousses et des racines sont notées (tableau 2, fig. 1). Les clones qui produisent plus grandes pousses tubérisent plus t?t et ont une durée de végétation plus courte. Ceux qui ont un ratio racines/pousses plus élevé ont un retard de tubérisation et une durée de végétation prolongée (tableau 3). Burton (1966), Raeuber & Engel (1963) suggèrent qu’un bon rendement correspond à un développement précoce et rapide de la plante et à une végétation prolongée. Les résultats montrent que ces éléments peuvent être déterminés de fa?on simple en début de végétation des clones: un poids de pousse élevé indique un développement rapide et précoce et un rapport racines/pousses élevé indique une végétation de longue durée. Dans le matériel expérimenté, 2 clones présentaient à la fois le poids de pousses le plus élevé et le ratio racines/pousses le plus élevé (fig. 1). La possibilité d’utiliser les résultats pour la création de variétés productives est discutée.

     

Genetic parameters in Finnish blue fox population: Pelt character and live animal grading traits

Abstract

Finnish blue fox farmers breed for increased litter size and pelt size, and improved fur quality. Some farmers select pelt size and fur quality indirectly using live animal evaluations (grading traits). In order to be able to define breeding goals properly, heritabilities and genetic correlations were estimated for size traits and fur quality traits. There were four pelt character traits (pelt size, pelt colour darkness, pelt colour clarity and pelt quality) measured on dried skins, and six grading traits (animal size, grading colour darkness, grading colour clarity, underfur density, guard hair coverage and grading quality). The data included 54,680 animals born during the years 1987–2002, originating from seven farms. The heritabilities were high for pelt colour darkness and grading colour darkness, moderate for pelt size and low for other traits. In general, heritability of a pelt character trait was higher than its corresponding grading trait. Genetic correlations within the pelt character traits were low (～0.11) and within the grading traits mainly moderate or high (～0.44). There was high genetic correlation between pelt darkness and grading darkness, pelt quality and grading density, pelt size and animal size; between pelt quality and grading quality and between pelt colour darkness and grading guard hair coverage. This suggests that selection of pelt character traits via grading traits in most cases is relatively effective.     

Retention of applied p by volcanic ash soils ‐ influence on available p and soluble al

Abstract

Most fertilizer (and lime) recommendations are based on: i) a level of available nutrient (or pH) sufficient for at least near‐maximum crop yields and ii) an average rate of buildup of the available nutrient (or pH) per unit of fertilizer (or lime) added.

Soils differ widely in the rate of buildup of available nutrient per unit of added fertilizer. Soil type (or association) is generally not available for individual soil samples submitted for testing. Even if it were, research information is generally inadequate to adjust the recommendations with any great degree of accuracy on this basis alone. Thus it seems imperative that new tests and/or equilibrations for individual soil samples be developed to provide the information needed. Recent results by us and others seems to offer hope of success in such efforts.

Lime and fertilizer costs are a substantial portion of the total production costs in modern farming. Thus, it is important that the rates recommended be the best possible for the individual soil, crop, and farming situation. The question of how good our current recommendations are is examined, as is that of how they might be improved with some possible refinements. In order to be brief, use is made of charts, most of which have appeared in previous papers.     

Genetic analysis for oil and protein contents of rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) at different developmental times

The dynamic expression of genes for oil and protein contents of rapeseed (Brassica napus L.) was carried out with time-dependent measures by using the developmental genetic models for quantitative traits in diploid plant. The unconditional and conditional analysis showed that the accumulated genetic effects or net genetic effects from diploid embryo nuclear genes, cytoplasmic genes and diploid maternal plant nuclear genes were all important for the performance of both nutrient quality traits at most developmental times/stages. Results from the conditional analysis further revealed that the activation of quantitative genes was gradually carried through the developmental process with maternal genes playing more active role at most developmental stages. Additive effects from embryo and maternal plant were found more important than the dominant effects at most developmental times/stages for both traits, and especially for protein content of rapeseed. Heritability analysis confirmed that the maternal heritability for protein contents were considerably stronger throughout developmental period except for the developmental time at 22 days, while for oil content the heritability components were dynamic and time dependent. The differences of genetic relationships from various genetic systems were found for oil and protein contents among the developmental times or between the two quality traits. M. T. Variath and J. G. Wu are contributed equally to this paper.     

Genetic parameter estimates for prenatal and postnatal mortality in Nellore cattle

The aim of this study was to estimate genetic parameters for prenatal (PRE) and postnatal (POS) mortality in Nellore cattle. A total of 13 141 (PRE) and 17 818 (POS) records from Nellore females were used. PRE and POS were recorded using binary scale scores: a score of ‘1’ was given to calves that were born alive (PRE) and those that were alive at weaning (POS), and a score of ‘0’ was given to calves that were not alive at or around birth (PRE), as well as to those weighed at birth but not at weaning (POS). The relationship matrix included 698 sires, 107 paternal grandsires and 69 maternal grandsires. Data were analysed using Bayesian inference and a sire–maternal grandsire threshold model, including contemporary groups as random effects, and the classes of dam age at the beginning of mating season (for PRE), and dam age at calving and birthweight (linear covariable) (for POS), as fixed effects. For both traits, the covariance between direct and maternal effects (r_D,M) was estimated (r_D,M≠ 0) or fixed at zero (r_D,M = 0). PRE and POS rates were 3.00 and 4.04%, respectively. Estimates of direct and maternal heritability were 0.07 and 0.17, respectively, for PRE, and 0.02 and 0.07, respectively, for POS, assuming r_D,M = 0. For r_D,M ≠ 0, these estimates were 0.07 and 0.12, respectively, for PRE, and 0.03 and 0.07, respectively, for POS. The correlation estimates between direct and maternal effects were ?0.71 (PRE) and ?0.33 (POS). PRE and POS show low genetic variability, indicating that these traits probably suffer major environmental influences. Additionally, our study shows that the maternal genetic component affects preweaning calf mortality twice as much (or more) as the direct genetic component. A large number of offspring per sire is necessary in progeny tests to genetically decrease calf mortality.     

润楠属7个种木质部导管特征研究

指出了润楠属为樟科常绿植物,具有较高的经济价值,但其自然资源保护措施不到位,生理生态理论研究比较缺乏。对润楠属7个种的木质部导管特征,包括导管密度(CD)、导管面积(CA)和导管壁加固系数(CWR)进行了研究,试图寻找其相互关系,为润楠属的生理生态研究提供理论基础。结果表明:润楠属的导管密度与导管壁加固系数呈极显著正相关;导管面积与导管壁加固系数呈显著正相关;导管密度和导管面积不具有相关性。     

大白猪繁殖和生产性状母体遗传效应估计

用非求导约束最大似然法估计了大白猪部分性状的直接和母体遗传效应。总产仔数,活产仔数和初生重的直接效应遗传力分别为０．１５,０．２５和０．０９,母体效应的遗传力分别为０．１２,０．１９和０．６４,直接和母体效应间遗传相关分别为－０．５４,－０．１８,和０．６６。     

广义复相关系数及其在小麦育种上的应用

为了解决多个因变量Y和多个自变量X之间的相关分析,假设X与Y的联合正态分布已知,而且X与Y存在线性相依,提出广义复相关系数的定义、估计和检验。广义复相关系数是简单相关系数和复相关系数的自然推广,应用上更为方便。     

Genetic parameters for carcass and meat quality traits and their relationships to liveweight and wool production in hogget Merino rams.

Genetic parameters for carcass and meat quality traits of about 18-month-old Merino rams (n = 5870), the progeny of 543 sires from three research resource flocks, were estimated. The estimates of heritability for hot carcass weight (HCW) and the various fat and muscle dimension measurements were moderate and ranged from 0.20 to 0.37. The brightness of meat (colour L*, 0.18 +/- 0.03 standard error) and meat pH (0.22 +/- 0.03) also had moderate estimates of heritability, although meat relative redness (colour a*, 0.10 +/- 0.03) and relative yellowness (colour b*, 0.10 +/- 0.03) were lower. Heritability estimates for live weights were moderate and ranged from 0.29 to 0.41 with significant permanent maternal environmental effects (0.13 to 0.10). The heritability estimates for the hogget wool traits were moderate to high and ranged from 0.27 to 0.60. The ultrasound measurements of fat depth (FATUS) and eye muscle depth (EMDUS) on live animals were highly genetically correlated with the corresponding carcass measurements (0.69 +/- 0.09 FATC and 0.77 +/- 0.07 EMD). Carcass tissue depth (FATGR) had moderate to low genetic correlations with carcass muscle measurements [0.18 +/- 0.10 EMD and 0.05 +/- 0.10 eye muscle area (EMA)], while those with FATC were negative. The genetic correlation between EMD and eye muscle width (EMW) was 0.41 +/- 0.08, while EMA was highly correlated with EMD (0.89 +/- 0.0) and EMW (0.78 +/- 0.04). The genetic correlations for muscle colour with muscle measurements were moderately negative, while those with fat measurements were close to zero. Meat pH was positively correlated with muscle measurements (0.14 to 0.17) and negatively correlated with fat measurements (-0.06 to -0.18). EMDUS also showed a similar pattern of correlations to EMD with meat quality indicator traits, although FATUS had positive correlations with these traits which were generally smaller than their standard error. The genetic correlations among the meat colour traits were high and positive while those with meat pH were high and negative, which were all in the favourable direction. Generally, phenotypic correlations were similar or slightly lower than the corresponding genetic correlations. There were generally small to moderate negative genetic correlations between clean fleece weight (CFW) and carcass fat traits while those with muscle traits were close to zero. As the Merino is already a relatively lean breed, this implies that particular attention should be given to this relationship in Merino breeding programmes to prevent the reduction of fat reserves as a correlated response to selection for increased fleece weight. The ultrasound scan traits generally showed a similar pattern to the corresponding carcass fat and muscle traits. There was a small unfavourable genetic correlation between CFW and meat pH (0.19 +/- 0.07).