alistic: the host provides the endophyte with shelter, nutrients, and an easy means of propagation; the fungus Tall fescue [Festuca arundinacea Schreb. var. arundinacea Schreb. improves its host survival through enhanced growth and (2n ϭ 6x ϭ 42)] breeding objectives are to exploit the natural variation fertility, better drought tolerance, increased resistance of the associated endophytic fungi and to select specific plant-fungus combinations that optimize the host fitness but do not cause detrimen-to pests and diseases, and a more efficient utilization of tal effects on grazing animals. This study investigated the presence soil nitrogen and phosphorus (Wilkinson and Schardl, of endophytes in 60 tall fescue natural populations from Sardinia, Italy; and short-conidia endophyte variants, the latter producing only about entiation, alkaloid pattern production, and conidia and 25% of the ergovaline produced by the former. A coevolutionary colony morphology, revealed remarkable morphologispecificity between the native Sardinian fescue germplasm and its cal and biochemical variation among isolates. They deassociated endophyte was suggested by the agreement between morscribed two new taxonomic groupings (FaTG ϭ Festuca phology of the host plant (distinct from germplasm originating in temperate environments) and morphological and biochemical charac-arundinacea Taxonomic Grouping) distinct from N. coeteristics of the harbored fungus.
The Sequence-Specific Amplification Polymorphism (S-SAP) method, recently derived from the Amplified Fragment Length Polymorphism (AFLP) technique, produces amplified fragments containing a retrotransposon LTR sequence at one end and a host restriction site at the other. We report the application of this procedure to the LTR of the Tms1 element from Medicago sativa L. Genomic dot-blot analysis indicated that Tms1 LTRs represent about 0.056% of the M. sativa genome, corresponding to 16 x 10(3) copies per haploid genome. An average of 66 markers were amplified for each primer combination. Overall 49 polymorphic fragments were reliably scored and mapped in a F(1) population obtained by crossing diploid M. falcata with M. coerulea. The utility of the LTR S-SAP markers was higher than that of AFLP or SAMPL (Selective Amplification of Microsatellite Polymorphic Loci) markers. The efficiency index of the LTR S-SAP assay was 28.3, whereas the corresponding values for AFLP and SAMPL markers were 21.1 and 16.7, respectively. The marker index for S-SAP was 13.1, compared to 8.8 for AFLP and 9.5 for SAMPL. Application of the Tms1 LTR-based S-SAP to double-stranded cDNA resulted in a complex banding pattern, demonstrating the presence of Tms1 LTRs within exons. As the technique was successfully applied to other species of the genus Medicago, it should prove suitable for studying genetic diversity within, and relatedness between, alfalfa species.
Post‐harvest residue removal is critical for high seed production of Kentucky bluegrass (Poa pratensis L.). Previous work showed some accessions have little yield reduction with mechanical removal of post‐harvest residue compared with the controversial practice of open‐field burning. Using 10 of these accessions, our objectives were (i) to relate seed yield and yield components in spaced plants to yield in row‐seeded plots, (ii) to link yield to growth and development factors, and (iii) to determine variation for seed production factors among accessions. Seed yield, seeds per panicle, panicle number, weight per seed, heading, anthesis, and harvest dates showed strong accession differences on spaced plants in 2002 and 2003. Yields in row‐seeded plots from 1998 and 1999 data were consistently correlated with yield per plant per area in spaced plants in 2002 (r = 0.75, P < 0.05) and 2003 (r = 0.90, P < 0.01). Turf quality was negatively correlated with yield per plant per area in 2002 and 2003 but was not consistently correlated with yield components. Days from heading to anthesis consistently correlated with yield per plant per area in 2002 (r = 0.81, P < 0.01) and 2003 (r = 0.85, P < 0.01). Variation for seed yield and yield components was observed within accessions both years and differed among accessions. The results show that seed yield per plant per area in spaced plants may be a useful predictor of yield in field stands and that a long heading to anthesis period promotes seeds per panicle and seed yield.
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