Search

Sugarcane (Saccharum spp.) is a crop of great economic importance that has been propagated by tissue culture through organogenesis and somatic embryogenesis. The present research had as objective to determine the phenotypic variability in the field of sugar cane cv. 'C87-51' plants obtained by somatic embryogenesis in liquid culture media. Plants regenerated from somatic embryos were planted in the field next to plants propagated via organogenesis and from cuttings that were used as control. The evaluations were carried out seven months after planting in cane plant and first shoot and the variables evaluated were stem height, stem diameter, number of stems per seedlings, number of active leaves per stem and Brix. Besides, morphological characteristics were described. Plants out of type were not found in the evaluated populations. The results demonstrated that the plant regeneration pathway significantly influences the development of plants under field conditions. The propagation of sugarcane plants cv. 'C87-51' by somatic embryogenesis in liquid culture medium only induces phenotypic changes in field associated with in vitro rejuvenation similar to those previously reported for plants obtained by organogenesis. Therefore, it can be used as a method of mass propagation of plants. [ABSTRACT FROM AUTHOR]

Choosing new genotypes of rice based on the probability of overcoming the test-check. The objective of this work was to validate a statistical methodology for estimating the reliability or normalized response (RNi) and stability of four elite rice genotypes, compared with the control IDIAP 145-05. We used the database from the rice breeding program IDIAP, from experiments conducted from 2009 to 2011, in 31 environments under dryland conditions. The results of the study allowed us to verify that new genotypes significantly exceeded (P<0.05) in grain yield the control used. The four genotypes IDIAP FL 106-11, 137-11 FL IDIAP, IDIAP FL 155 and FL 156 IDIAP had a reliability average of 0.79, 0.75, 0.75 and 0.74, respectively. The normalized probability IDIAP FL 106-11 represents a differential response greater than zero with respect to IDIAP 145-05, in 8 of 10 cases. It also confirmed the reliability is related to the stability parameters based on regression models (bi and S²di). The AMMI multivariate model, considering the PCA1, identified the genotype IDIAP FL 156, as the most stable. GGE Biplot model, based on the PCA2, found that the genotype IDIAP FL 155, had greater stability. The study illustrates that the reliability or standardized response may be useful for more precise recommendations for the use of new genotypes commercially. [ABSTRACT FROM AUTHOR]

Fusarium mexicanum has been described as the causal agent of mango malformation in several producing areas in Mexico. Isolates of F. mexicanum obtained from mango trees with malformation disease in Jalisco were characterized according to vegetative compatibility groups (VCGs). Isolates were cultured on minimal medium - supplemented with potassium chlorate (KClO3), NO3-, and L-asparagine, to generate spontaneous nitrate nonutilizing (nit) mutants. Mutants are detected as mycelia sectors chlorate-resistant, which are not able to utilize nitrate as a nitrogen source due to mutations at loci associated with the nitrate-assimilation pathway. F. mexicanum isolates generated 239 chlorate-resistant sectors of mycelia, out of 62.3 % were nit mutants. Phenotypic characterization detected 36.91 % mutants nit1, 28.18 % mutants nit3, 19.46 % mutants NitM and 14.76 % mutants nnu. Compatibility pairing tests amongst the mutants detected two VCGs in isolates of F. mexicanum from Jalisco. Isolates in one VCG from Jalisco were compatible with isolates of a previously identified VCG of F. mexicanum from Michoacan. A total of three VCGs were detected in the central Pacific region of Mexico. [ABSTRACT FROM AUTHOR]

Conventional plant breeding is primarily based on phenotypic selection of superior individuals among segregating progenies resulting from hybridization. It is often time consuming as breeding a new cultivar takes between eight and ten years and even then, the release of improved cultivar is not guaranteed. Hence, breeders are extremely interested in new technologies that could make this procedure more efficient. Marker-assisted selection, often simply referred to as Marker-Assisted Selection (MAS) offers such a possibility by adopting a wide range of novel approaches to improving the selection strategies in crop breeding. Molecular markers are powerful research tools that make it possible to determine the genetic makeup of plants; for that it is possible the selection by plants genotype. In this paper, we refer the significant advancements towards application of molecular marker technology for crop improvement in the last decade, in tomato. Finally, we discuss reasons why the greater adoption of MAS in the future is inevitable, although the extent of its use will depend on available resources, and may be delayed in less-developed countries. [ABSTRACT FROM AUTHOR]