Search

Lucerne (Medicago sativa L.) is a major perennial forage legume worldwide. In Greece, new cultivars have been introduced mainly from the USA, Australia and Italy. However, some of these cultivars have not been tested locally before their widespread release. A field experiment was conducted from 2013 to 2016 in central Greece to compare the performance of 22 lucerne genotypes, including both local Greek and introduced genotypes, under irrigated Mediterranean conditions. There were three harvests in 2013 and five in each of the following years. Measurements included annual and total dry matter (DM) yield, harvest ratios, quality traits and agronomic parameters. Yields after the second year declined by 11.9–26.4%, possibly due to summer heat stress and reduced plant survival. However, several semi-winter-active cultivars were more persistent (by 19.4%) than highly winter-active cultivars. Three local, semi-winter-active cultivars and one introduced highly winter-active cultivar were the top performers for total DM yield (63.8–67.3 t DM/ha). Forage nutritive values showed small differences among cultivars. Evaluation of seasonal yield distribution was effective for comparing adaptive responses of genotypes in relation to the winter activity effect. Spring harvest ratio was more indicative (r = 0.92) of genotype total DM yield than was plant survival (r = 0.70). Specifically, highly winter-active cultivars showed higher autumn and spring harvests (by 36.4% and 7.9%, respectively) than semi-winter-active cultivars, which produced higher summer yields (by 35.7%). A regional program to breed more winter-active genotypes, which can capitalise on the longer preceding season with greater stand persistence, heat tolerance, summer productivity and height (>82 cm) and with more nodes (>18), could be beneficial for forage yield increase under the anticipated climatic changes.

Twenty alfalfa cultivars were tested, under rainfed conditions in central Greece, for forage yield, agronomic and nutritive value in order to identify adaptive responses contributing to high resilience and productivity. From 2014 to 2017, five harvests (H1 to H5) per season were conducted. Two cultivars were also grown as irrigated checks. Annual and total dry matter (DMA and DMT) and harvest ratios (RH) were estimated. DMT was reduced by 42.9–48.1% under ambient rainfall compared to irrigated checks, which received 50.2% more water. The seasonal yield distribution demonstrated two contrasting strategies, however, equally effective for high resilience under rainfed conditions. The winter-active imported cultivars were the most resilient in the driest year, potentially due to their ability to exploit autumn rains, whereas the locally adapted genotypes were more productive in summer. The spring harvest ratio (RH1) was more indicative (r = 0.94, P < 0.01) of cultivar productivity, compared to plant survival (r = 0.65, P < 0.01), whereas the autumn harvest ratio (RH5) was representative of productivity under extreme drought (r = 0.53, P < 0.05). RH1 and RH5 were increased by 11.8 and 12.3%, respectively, whereas the summer ratios (RH3, RH4) were reduced by 47.3%, under rainfed v. irrigated conditions. Two Australian cultivars (‘Blue Ace’, ‘Icon’) achieved the highest RH5 suggesting an adaptive response by being more productive in autumn. However, the development of specifically adapted cultivars in terms of higher summer yield and plant survival may be necessary to cope with future climatic changes in the Mediterranean region.

SUMMARYThe number of replications and locations used in a cultivar evaluation scheme is an important factor affecting the trial heritability (H) and optimum resource allocation. The aim of the present study was to calculate the required number of replications and locations for realizing an optimumHof 0·75 and to identify the most effective test locations for cotton (Gossypium hirsutumL.) in Greece. The data for lint yield, plant height, verticillium wilt (Verticillium dahliaeKleb.) and fibre quality were derived from an 8-year experiment (2000–2007) conducted under irrigated, Mediterranean conditions at 14 locations along the Greek mega-environment. Analysis of variance was performed to calculateHas well as genotype plus genotype × environment (GGE) biplot analysis to determine the location's desirability. It was determined that the four replications currently used in the evaluation of lint yield were sufficient, whereas four locations were proposed as optimum in lieu of the current 8–14 locations used in the evaluation. Two locations excelled as the most effective for lint yield evaluation and one for selection of genotypes tolerant to verticillium wilt using as criteria: the high and consistent across yearsH(0·75), GGE biplot representativeness and discriminating ability. Moreover, one location was selected as a backup based on average trial failures. Plant height was sufficiently evaluated by four replications and two locations, while verticillium required four replications for realizing lowerH(0·60) and three locations for even lowerH(0·40). Regarding quality, an increase of replications from the two currently used to four was sufficient for evaluation of all the traits. The advantage of reducing the number of locations for evaluation of lint yield to just four casts no doubt on the evaluation precision of lint percentage, length, strength and elongation but does for micronaire, short fibre index and uniformity, which realized lowerH(0·60 or 0·50).

SUMMARYWinter rapeseed was introduced into Greece a decade ago to provide oil for biodiesel. To identify agronomic traits affecting yield and quality, three hybrids and an inbred line were tested over two seasons (2005–2006 and 2006–2007) and four locations, in central and northern Greece, varying in pedo-climatic conditions. The large variations in seed yield, quality and agronomic traits were largely ascribed to location; in contrast, cultivar accounted for ⩽0·010 of the variation for many traits. Below 40°N, rapeseed is a risky crop; short season, high temperatures and low rainfall during reproductive growth diminished seed yield and oil content, increased oleic and erucic acid and minimized linolenic acid. A hybrid, Exact, with tall stature and large seeds was adaptive to such conditions. The most productive location had dense stands with tall plants bearing numerous pods on the main raceme. At the site with the coldest winter, plant density (PD) was lowest (ca. 30 plants/m2) but rapeseed compensated by producing large seeds, with high oil content and harvest index (HI). A biplot revealed that the hybrid Excalibur, outperforming the other cultivars for oil content in six out of eight trials, produced the highest and most stable oil yield. Combined data showed that seed yield and oil yield were positively correlated with PD, seed size and HI and negatively to the number of pods on branches and per plant. Large seeds had high seed oil content. Oleic acid was negatively correlated to linolenic acid concentration. High temperatures and low rainfall favoured oleic acid, which was positively associated with seed number per pod.

Common bean is the most significant pulse in Mediterranean countries and high yield performance is required to become commercially successful. Seven common bean genotypes were evaluated for yield and stability along with their interrelationship with agronomical, physicochemical and quality characteristics. An analysis of variance was conducted to test main effects and interactions between plant traits and environments. Significant variation among genotypes occurred for seed yield and a strong positive correlation was observed between seed yield and pods m-2. High Genetic Coefficient of Variation (GCV) values combined with high heritability for traits as seed yield, cooking time, hydration capacity and protein content were recorded. The GGE biplot analysis indicated two cultivars as superior genotypes that combine high yield, stability, short cooking time and high protein content. Furthermore, a local population assessed as promising genetic material for the selection of elite lines with high yield and short cooking time.

Cultivar mixtures are suggested for low-input farming systems because they introduce functional diversity. The lack of common vetch (Vicia sativa L.) cultivars bred for and adapted to low-input farming systems raises the issue of whether the mixtures composed from varieties developed under conventional conditions can satisfy the demands of low-input agriculture. The objective of this project was to evaluate the performance of fi ve common vetch varieties and mixtures of these varieties in a low-input system. Three-year preliminary experiments were conducted among widely adapted cultivars bred under high-input conditions to select the most productive cultivars. Thus, fi ve common vetch cultivars and their mixtures were evaluated under low-input farming system (2007–2009). Dry matter (DM) production and crude protein content were measured for each entry. Mixture effect (ME) was calculated to measure the relative performance of a mixture over its components. Genotype main effect plus genotype × environment interaction (GGE) biplot analysis was used to assess yield and stability. It was observed that ME for DM was positive for three mixtures over environments and ranged from 0.19 to 4.63 Mg ha −1 . GGE biplot analysis indicated that two of the previous three mixtures exhibited the greatest yield and stability. Crude protein values of the mixtures were at least comparable with their individual cultivar components. These results showed considerable advantages of mixing common vetch cultivars bred under high-input conditions for use in low-input farming system.