The effect of photoperiod and temperature on yield in beans

Photoperiod insensitivity in the germplasm collection of beans (Phaseolus vulgaris) held at CIAT is found mostly in accessions from higher latitudes. Cold tolerance is found in accessions from the high Andes, but these are all photoperiod sensitive. A break in adaptation seems to occur at about 15 degrees C, between accessions specifically adapted to cool or warm temperatures. Those adapted to cool temperatures tend to have large seeds. An attempt is being made to combine adaptation to growing and yielding at low temperature with photoperiod insensitivity. A number of breeding lines have been selected which combine improved cold temperature tolerance with photoperiod insensitivity (e.g. VRA 81078, VRA 81072). The extent to which production regions of the world can be stratified according to the optimum photoperiod/temperature response required in bean cultivars is being studied in an international phenology nursery organized collaboratively by Cornell University and CIAT. (AS

Graph products of spheres, associative graded algebras and Hilbert series

Given a finite, simple, vertex-weighted graph, we construct a graded associative (non-commutative) algebra, whose generators correspond to vertices and whose ideal of relations has generators that are graded commutators corresponding to edges. We show that the Hilbert series of this algebra is the inverse of the clique polynomial of the graph. Using this result it easy to recognize if the ideal is inert, from which strong results on the algebra follow. Non-commutative Grobner bases play an important role in our proof. There is an interesting application to toric topology. This algebra arises naturally from a partial product of spheres, which is a special case of a generalized moment-angle complex. We apply our result to the loop-space homology of this space.Comment: 19 pages, v3: elaborated on connections to related work, added more citations, to appear in Mathematische Zeitschrif

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Interacciones de genotipos por sistema de cultivo en frijol y maiz

The results are presented of 3 expt conducted at CIAT to improve var. destined for use in multiple-cropping systems; (1) evaluation of bean var. (bush and climbing) in 2 cropping systems, monoculture and in association with maize; (2) evaluation of 20 maize genotypes in monoculture and in association with 2 bean types (habits II and IV); and (3) evaluation of 3 maize and 10 climbing bean genotypes. It is concluded that there are certain genotypic combinations of maize and beans that are better but that are not necessarily the best for monoculture. Nevertheless, evidence indicates that when certain simple plant characteristics are taken into account for both maize and beans, better combinations can be predicted. (CIAT

Metodologia de la investigacion aplicada a la asociacion frijol- maiz

Three trials were carried out at CIAT-Palmira to quantify the effect of plot edges and useful plot size in beans. In the 1st trial (sown in Oct. 1977), the competition effect of 36 climbing bean var. associated with maize ICA H-210 in adjacent plots and the effect of the alleys on plot edges were studied. The harvested plot area was directly proportional to the F test value for var. effect, and inversely proportional to C.V. The effect of lateral edges was not significant. The effect of headland edges for 2 and 4 seed beds was influenced by the var. Light utilization was different in all the var. Yields of most productive bean var. were less overstimated when headland edges were included. The 2nd trial was sown with 3 replications, using climbing bean var. P589 and maize ICA H-207. The 3rd trial had 4 replications with the same bean var. associated with maize ICA H-210. Results of the 2nd trial show a min. effect of 2-m edges, with a greater effect for the association than for the monocrops. Beans in association acted as an anchorage to maize, thus reducing lodging. It is concluded that there was no need to leave lateral edges between plots, since there was not a significant competition effect between adjacent plots. A marked effect of headland edges was observed, not uniform for all the var. A useful plot of 11 square meters is required for climbing bean associated with maize, to detect a significant 24 percent difference over the mean, with 4 replications. Various quantification methods of the association system as a whole and regarding each component in monoculture are described and compared. Tables and figures illustrating exptl. results are included. (CIAT

Orientacion del mejoramiento de frijoles volubles

The method of selection used by CIATs climbing bean program is between the pedigree method (lineage) and the bulk population method. This method reduces the variation of each hybrid population in F, by individual selection. The evaluation of the germplasm bank was conducted in Popayan (1850 m above sea level), Antioquia (2200 m above sea level) and Pasto (2700 m in alt.) to find disease-resistance, appropriate growth habit and adaptation. The selected var. were tested for resistance to BCMV races and anthracnose in the greenhouse. The appropriate method was backcrossing in this case. Crossbreeding followed by selection in the field is used to increase yield potential, the level of tolerance to certain diseases and adaptability. In maize/bean associations, it is recommended to select crosses or lines of 2 crosses together. The strategy of selection used is summed-up in table form. (CIAT

Mejoramiento de frijoles volubles para sistemas de siembra de asociacion con maiz

Maize and climbing beans are traditionally planted in association in the sierra regions of L.A. with alt. higher than 1500 m. The system has shown a series of advantages: low incidence of certain pests and diseases, less root lodging in maize, and less risk for the farmers. The types of climbing bean and maize used in associated cropping systems were studied. In general, maize and bean yields were negatively related and it was found that yields of tall maize genotypes were less affected by beans than short maize genotypes. Root lodging of tall maize genotypes was notably reduced in association. Stem lodging of short maize genotypes was due to the vigorous growth of some climbing bean var. Very vigorous bean var. could not reach their own yield potential with short maize genotypes due to the poor support system. In yield trials with climbing bean breeding material, both relay and associated cropping systems with maize had lower costs than beans in monoculture as well as being the most representative system used by farmers. Yields of bean genotypes in association were generaly lower and had less significant differences than in monoculture. It was concluded that with an appropriate management of plot size and border effects, climbing bean yields were higher in association and were favorably assessed from an economic standpoint. (AS-CIAT