This investigation examined the efficiency of various screening procedures which could be used in breeding for increased production of root-proliferating (RP) genotypes of alfalfa (Medicago sativa L. s. l.). Also investigated were relationships between RP and winter growth characteristics in populations derived from crosses between dormant, RP clones and nondormant, non-RP clones. In addition, this investigation also considered the inheritance of the RP habit. Plants from an 11-month F₁ progeny test containing 3508 offspring were qualitatively analyzed for RP expression using three pairs of screening procedures. Procedures compared included: (1) direct-seeding vs. transplanting; (2) use of characterized parental clones (known RP-expressing genotypes selected from field nursery) vs. uncharacterized parental clones (genotypes derived from RP seed lots with no prior knowledge of their ability to express the RP habit) in RP x nondormant crosses; and (3) low vs. high harvest frequencies. A low frequency (3.3%) of F₁ plants exhibited adventitious shoot formation. No differences were observed in the frequency of RP-expressing genotypes between the direct-seeded and transplanted treatments or between the low and high harvest frequency treatments. Characterized RP parents produced a hybrid population with a significantly higher frequency of RP-expressing genotypes than did the F₁ population derived from uncharacterized RP parents. Average winter forage production of the F₁ hybrids were similar in magnitude to the midparent value. Plant height was significantly and positively correlated with forage yield and could be used as an accurate indicator of winter forage yield in analyses of RP segregants. Estimates of components of genetic variance for RP expressivity indicated a predominance of additive effects and narrow sense heritability of 8.4%. Family selection and progeny testing are suggested for maximum breeding progress.

No description available.

No description available.

No description available.

Thesis (MTech (Agriculture))--Cape Technikon, 1998. / The drymatter - and animal production of nine lucerne cultivars were evaluated under dryland conditions with SA Mutton Merino sheep at Outeniqua Experimental Farm (George). The nine lucerne cultivars that were chosen for this experiment, were already evaluated in cutting trials for their drymatter production. They consist of one winterdormant cultivar (Alfagraze), two semi-winterdormant cultivars (WL 320 and Meteor), five intermediate-winterdormant cultivars (SA Standard, Standard Tygerhoek, Aurora, Diamond and WL Southern Special) and one winteractive cultivar (Cuf 101). The mild climate of this area resulted mainly in a difference in drymatter production between the most winterdormant cultivar (Alfagraze) and winteractive cultivar (Cuf 101). The only difference in the rate of production of winterdormant types appear in winter and spring. The production rate of the winterdormant and semi-winterdormant cultivars was lower in the winter than that of the intermediate winterdormant (WL Southern Special) and the winteractive cultivar (Cuf 101). The drymatter production of the semi-winterdormant cultivar (WL 320) was higher than that of the winteractive cultivar (Cuf 101) in spring. There is a seasonal difference in the drymatter production of lucerne cultivars from the same winterdormancy class. Some of the more winterdormant cultivars also achieve a comparable and even higher dry matter production than that of the more winteractive cultivars. This tendancy is prominant between the semi-winterdormant cultivars (WL 320 and Meteor). WL 320 has a higher dry matter production than Meteor. It also has a higher or equal production rate, dependant on the seasons, than the winteractive cultivar (Cuf 101). A similar tendancy appears in the intermediatewinterdormant cultivar (WL Southern Special). The seasonal drymatter production and production rate of this cultivar are the same as that of Cuf 101. The appearance of annual grasses and weeds had a seasonal influence on the availability of dry matter and animal production. The grass production increases over the years resulting in up to 20% increase of the green matter during winter and spring. The grazing capacity of the winterdormant cultivar (Alfagraze) has increased during this seasonal grass production. The lucerne cultivar with the highest drymatter production rate and the highest seasonal dry matter production, also had the highest grazing capacity. The yearly and seasonal grazing capacity of WL 320, Aurora, WL Southern Special and Cuf 101 was generally higher than most of the other cultivars. This was also the most important reason for the high live mass increase with these cultivars.

One of the limiting factors associated with seed production of alfalfa and certain clovers is a small jet-black wasp commonly known as the clover seed chalcid, Bruchophagus gibbus (Boheman). In alfalfa seed producing areas this insect is often referred to as the alfalfa seed chalcid or the alfalfa seed chalcis-fly. In local areas of Utah, farmers often refer to this insect as simply "the fly."

New alfalfa varieties are constantly being introduced into the marketplace. The number of varieties available for low-elevation desert areas in Arizona in the non-dormant class is over50. New varieties are introduced each year and unbiased yield comparisons are helpful to the grower to base the decision of whether or not to sow a new variety. The study reported here is part of the on-going effort to evaluate alfalfa variety performance in Arizona. A summary of alfalfa variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1267.pdf.

New alfalfa varieties are constantly being introduced into the marketplace. The number of varieties available for low-elevation desert areas in Arizona in the non-dormant class is aver50. New varieties are introduced each year and unbiased yield comparisons are helpful to the grower to base the decision of whether or not to sow a new variety. The study reported here is part of the ongoing effort to evaluate alfalfa variety performance in Arizona. A summary of alfalfa variety trials conducted by the University of Arizona can be found online at http://ag.arizona.edu/pubs/crops/az1267.pdf.

No description available.

No description available.