Selection of winter cereals for organic agriculture

Productivity in agriculture has more than tripled in developed countries since the 1950s. Beyond the success of plant breeding, the increased use of inorganic fertilizers, application of pesticides, and spread of irrigation also contributed to this success. However, impressive yield increases started to decline in the 1980s because of the lack of sustainability. One of the most beneficial ways to increase sustainability is organic agriculture. In such systems the prerequisite of successful farming is the availability of crop genotypes that perform well. However, selection of winter cereals for sub-optimal growing conditions is still neglected, and the organic seed market also lacks of information on credibly tested varieties suitable for organic agriculture

Performance and selection of winter durum wheat genotypes in different European conventional and organic fields

Sustainability is a key factor for the future of agriculture. Productivity in agriculture has more than tripled in developed countries since the 1950s. Beyond the success of plant breeding, the increased use of inorganic fertilizers, application of pesticides, and spread of irrigation also contributed to this success. However, impressive yield increases started to decline in the 1980s because of the lack of sustainability. One of the most beneficial ways to increase sustainability is organic agriculture. In such agro-ecosystem-based holistic production systems the prerequisite of successful farming is the availability of crop genotypes that perform well. However, selection of winter durum wheat for sub-optimal growing conditions is still mainly neglected, and the organic seed market also lacks of information on credibly tested winter durum varieties suitable for organic agriculture

Magnitude-range brightness variations of overactive K giants

We study three representative, overactive spotted K giants (IL Hya, XX Tri, and DM UMa) known to exhibit V-band light variations between 0.65-1.05 mags. Our aim is to find the origin of their large brightness variation. We employ long-term phase-resolved multicolor photometry, mostly from automatic telescopes, covering 42 yr for IL Hya, 28 yr for XX Tri, and 34 yr for DM UMa. For one target, IL Hya, we present a new Doppler image from NSO data taken in late 1996. Effective temperatures for our targets are determined from all well-sampled observing epochs and are based on a V-I_C color-index calibration. The effective temperature change between the extrema of the rotational modulation for IL Hya and XX Tri is in the range 50-200 K. The bolometric flux during maximum of the rotational modulation, i.e., the least spotted states, varied by up to 39% in IL Hya and up to 54% in XX Tri over the course of our observations. We emphasize that for IL Hya this is just about half of the total luminosity variation that can be explained by the photospheric temperature (spots/faculae) changes, while for XX Tri it is even about one third. The long-term, 0.6 mag V-band variation of DM UMa is more difficult to explain because little or no B-V color index change is observed on the same timescale. Placing the three stars with their light and color variations into H-R diagrams, we find that their overall luminosities are generally too low compared to predictions from current evolutionary tracks. A change in the stellar radius due to strong and variable magnetic fields during activity cycles likely plays a role in explaining the anomalous brightness and luminosity of our three targets. At least for IL Hya, a radius change of about 9% is suggested from m_bol and T_eff, and is supported by independent vsin(i) measurements.Comment: 13 pages, 8 figures, accepted in A&

Relations and evolution in "Cheilanthes" ("Sinopteridaceae, Pteridophyta") in Macaronesia and Mediterranean area, deduced from genome analysis of their hybrids

Nine species of "Cheilantoid ferns" are known to grow in Macaronesia and the Mediterranean basin. Two of them (lacking a pseudo-indusium and having the basic chromosome number X = 29), both aggregate species which we prefer to retain in Notholaena, are not included in this study. The other seven species (with distinct pseudo-indusium and the basic chromosome number X = 30), which we accept as members of the genus Cheilanthes Sw. sensu stricto, were subjected to detailed genome analysis of their natural and experimentally produced hybrids and shown to represent an aggregate of four very distinct ancestral diploids and three allotetraploids. The latter must have once been formed by chromosome doubling in the three diploid hybrids of C. maderensis Lowe with the other three diploid species. Theoretically three more allotetraploids would be possible but their formation has obviously been prevented by the geographical separation of the three respective diploids. The most widely distributed of the tetraploids, i.e. C. pteridioides (Reich.) C.Chr. has also been resynthesized from its ancestors (still sympatric) under experimental conditions. The intermediate morphology of the allotetraploids (as compared with their diploid ancestors) is obviously the reason why their status and existence has so long escaped recognition in Europe. These seven species form a natural group and, in our opinion, should not be divided into sections.Se conocen nueve especies de "helechos Cheilantoides" que viven en Macaronesia y la cuenca Mediterranea. Dos de ellos, (sin pseudoindusio y con número cromosómico básico X = 29) que preferimos incluir en Notholaena, no se estudian en este trabajo. Las otras siete especies (con pseudoindusio y número cromosómico básico X = 30) que reconocemos como miembros del género Cheilanthes Sw. sensu stricto, fueron objeto de un análisis detallado del genoma de sus híbridos, tanto de los naturales, como de los producidos experimentalmente mostrando un agregado de cuatro ancestrales diploides muy distintos y tres alotetraploides. Estos últimos deben haberse formado por duplicación de los cromosomas en los tres híbridos diploides resultantes del cruzamiento de C. maderensis con las otras tres especies diploides. Teóricamente son posibles otros tres alotetraploides, pero su formación se ha impedido por la separación geográfica de los 3 diploides respectivos. Los tetraploides más ampliamente distribuidos, como por ejemplo Cheilanthes pteridioides (Reich.) C. Chr., han sido igualmente resintetizados a partir de sus ancestros bajo condiciones experimentales. La morfología intermedia de los alotetraploides (comparada con sus ancestros diploides) es obviamente la razón por la que su existencia y status han pasado inadvertidos en Europa. Estas siete especies forman un grupo natural que, en nuestra opinión, no debe ser dividido en secciones

An Improved Bound for First-Fit on Posets Without Two Long Incomparable Chains

It is known that the First-Fit algorithm for partitioning a poset P into chains uses relatively few chains when P does not have two incomparable chains each of size k. In particular, if P has width w then Bosek, Krawczyk, and Szczypka (SIAM J. Discrete Math., 23(4):1992--1999, 2010) proved an upper bound of ckw^{2} on the number of chains used by First-Fit for some constant c, while Joret and Milans (Order, 28(3):455--464, 2011) gave one of ck^{2}w. In this paper we prove an upper bound of the form ckw. This is best possible up to the value of c.Comment: v3: referees' comments incorporate

Comparison of bread wheat varieties with different breeding origin under organic and low input management

The aims of the study were to compare 37 bread wheat varieties with different breeding origin under conventional and organic farming conditions in Hungary and Austria for three years and to identify traits highly sensitive to management systems that could be separated according to their suggested selecting environments. According to the results, heading date, sensitivity to leaf rust and powdery mildew had high heritability, thus, for economic reasons, it is reasonable to select for these traits in conventional fields even if the selection target is organic agriculture. On the contrary, selection for grain yield, test weight, leaf-inclination and vigorous growth should be done later in the target environment. It was concluded that the selecting environment has measurable effects on the performance of bread wheat varieties. Our results could help organic breeders in their selection work, especially in the continental climatic zone of Europe