Stability Analysis of Agronomic Traits in Potato Cultivars of Different Origin     

Bogdan Flis  Leszek Domański  Ewa Zimnoch-Guzowska  Zsolt Polgar  Servando Á. Pousa  Andrzej Pawlak 《American Journal of Potato Research》2014,91(4):404-413

Potato (Solanum tuberosum ssp. tuberosum) cultivars are expected to express a stable level for traits important for growers and consumers. To investigate how this expectation was met by a set of 21 cultivars bred in Hungary, Poland and Spain, 2-year field experiments were carried out in these countries for the evaluation of tuber yield, starch content and yield, and occurrence of secondary growth of tubers. Stability in an agronomic sense was evaluated by the analysis of genotype by environment interaction (GE) using the Scheffé-Caliński mixed model. Unstable trait expression was indicated by the statistically significant share of GE in the variability contributed by a specific cultivar. This instability could lead to either complete or partial unpredictability. Stable trait expression was observed for 6–11 cultivars, depending on the trait. A significant genetic factor, which indicates broad adaptation, was rarely found. Stable expression of tuber yield occurred together with stable or predictable expression of both starch content and yield. Unstable expressions of tuber and starch yield were also associated. The stability or instability of secondary growth was not associated with stability or instability of the other measured traits. Analysis of GE interaction was useful for identifying stable or unstable responses and revealed the presence of incomplete stability or partial unpredictability as intermediate types of reaction.  相似文献   

Development and evaluation of a noninvasive marker cluster technique to assess three-dimensional kinematics of the distal portion of the forelimb in horses     

Hobbs SJ  Richards J  Matuszewski B  Brigden C 《American journal of veterinary research》2006,67(9):1511-1518

OBJECTIVE: To develop and evaluate a marker cluster set for measuring sagittal and extrasagittal movement of joints in the distal portion of the forelimb in ponies. ANIMALS: 4 ponies. PROCEDURES: 5 infrared cameras were positioned on a concrete walkway in a frontal-sagittal arc and calibrated. Four segments were defined: hoof, middle phalanx, proximal phalanx, and metacarpus. Rigid clusters with 4 retroreflective markers were placed on each segment. A static trial was recorded with additional anatomic markers on the medial and lateral joint lines. Those anatomic markers were removed, and kinematic data were recorded at 240 Hz during walking. An ensemble mean was computed from the 4 ponies from 5 replicates of the walks. Joint kinematic variables were calculated by use of the calibrated anatomical system technique. The design and error dispersion of each marker were evaluated. RESULTS: Marker clusters were quasiplanar, but variation in orientation error was reduced because the mean radii were > 10 times the largest error dispersion values. Measurements of sagittal rotations of the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints were similar to measurements obtained with bone-fixed triads, but larger discrepancies between the 2 methods were found for extrasagittal rotations. CONCLUSIONS AND CLINICAL RELEVANCE: Development of noninvasive methods for quantifying data pertaining to 3-dimensional motion in horses is important for advancement of clinical analysis. The technique used in the study enabled identification of flexion-extension motions with an acceptable degree of accuracy. Appropriate correction algorithms and improvements to the technique may enable future quantification of extrasagittal motions.  相似文献