No abstract

This study was focused on studying the genetic diversity among pasture grass cultivars using intersimple sequence repeats (ISSR) markers to determine their genetic background. Six grass cultivars were used in this study: two perennial ryegrass (Lolium perenne L.) cultivars (Aries and Quartet), two endophyte-free tall fescue (Festuca arundinacea Schreb.) cultivars (Fawn and K5666v) and two orchardgrass (Dactylis glomerata L.) cultivars (Tekapo and Niva). Analysis of the 15 selected ISSR primers among the six grass cultivars generated 77 bands, 66 (85.7%) of which were polymorphic. The two perennial ryegrasses cultivars (Aries and Quartet) were distinguished by a 600-bp amplification fragment produced by primer UBC807. The 500-bp amplification fragment was produced by primer UBC825, which was distinguished in Niva, but absent in Tekapo-orchard grass. Furthermore, Fawn-tall fescue was distinguished by a 400-bp amplification fragment produced by primer UBC825. The minimum genetic similarity (GS) value was obtained between the two orchard grass cultivars (Niva and Tekapo), while the maximum GS value was obtained between the two perennial ryegrasses cultivars (Aries and Quartet).

Alfalfa (Medicago sativa L.) haylage (silage) is an important component in feed rations for dairy and beef herds in the north‐central region. Weather conditions in this region during first cutting don't always allow adequate curing of forage for dry hay production, so alfalfa may be ensiled. This study was conducted to evaluate the effect of morning (AM) versus afternoon (PM) cutting time upon sugar content of fresh cut alfalfa and the lactic acid concentration of ensiled alfalfa in Michigan. The study was conducted over the 2001 and 2002 growing seasons at the Michigan State University farm in East Lansing, MI. PM cutting normally provided greater sugar content in harvested alfalfa than AM cutting, but there was no improvement in silage fermentation based on lactic acid content. There was also no difference between AM and PM cutting time on alfalfa crude protein, acid detergent fiber, and neutral detergent fiber contents.

Low-fertility soil is considered a major challenge for growing wheat (Triticum aestivum) in organic systems. The objective of this study was to identify spring wheat genotype(s) adapted to growing in organic systems with low-fertility soil compared with conventional systems in the central region of Saudi Arabia. Organic and conventional trials were established during the 2010, 2011 and 2012 growing seasons in the arid environment of central region of Saudi Arabia. Both trails were seeded in a sandy loam soil. Eight bread wheat genotypes were evaluated for the following parameters: grain and straw yields, grain-filling rate (GFR), days to heading (DTH), days to maturity (DTM), number of kernels per spike and 1000-kernel weight. The experiment was a randomized complete block design (RCBD) with four replications. The findings showed that there were significant differences in grain and straw yields between the two systems and among genotypes. The Egyptian genotypes 'Sids 12' and Early-line produced the highest grain yields (7.8 tons ha-1) in the conventional system, whereas in the organic system, Yocora Rojo (control genotype) and Early-line produced the highest yields (5.8 and 5.9 tons ha-1, respectively). Grain and straw yields were higher in 2011 and 2012 growing seasons compared to 2010. Early-line and ICARDA genotypes (IC8 and IC17) had the highest grain-filling rate, whereas the Australian genotypes (P5 and P3) and the local genotype 'Sama' had the lowest grain-filling rate. The genotype Early-line had the shortest time to heading and maturity in both systems. Therefore, Early-line and Yocora Rojo are promising bread wheat genotypes for organic production systems in low-fertility soil.

Qassim region is considered an urban, agricultural area in the Kingdom of Saudi Arabia. This region is characterized by dominant arid climate. Low fertility soil is considered a major challenge for the sustainable cultivation of wheat (Triticum aestivum L.). The objective of this study was to assess some agronomic characteristics of the wheat genotypes grown organically on low fertility soil. The experiments were conducted during the 2010 and 2011 growing seasons using eight bread wheat genotypes growing under conventional and organic farming systems at two different locations. measurements of the following parameters were collected: chlorophyll content, flag leaf area (cm 2 ), and Harvest Index. Findings demonstrate a difference between the conventional and organic farming systems in terms of the parameters under study. Results showed that the greatest chlorophyll content was recorded in IC17 genotype (51.3 SPAD) Genotype Sids 12 had the highest FLA (28.0 and 26.3) under the conventional and organic farming systems, respectively. E-line and YR had the highest harvest index under the organic farming system in both the seasons. For sustainable food production in arid regions using the organic farming system, wheat genotypes YR and E-line could be the most suitable.