Molecular Clock on a Neutral Network

The number of fixed mutations accumulated in an evolving population often displays a variance that is significantly larger than the mean (the overdispersed molecular clock). By examining a generic evolutionary process on a neutral network of high-fitness genotypes, we establish a formalism for computing all cumulants of the full probability distribution of accumulated mutations in terms of graph properties of the neutral network, and use the formalism to prove overdispersion of the molecular clock. We further show that significant overdispersion arises naturally in evolution when the neutral network is highly sparse, exhibits large global fluctuations in neutrality, and small local fluctuations in neutrality. The results are also relevant for elucidating the topological structure of a neutral network from empirical measurements of the substitution process.Comment: 10 page

Pasture deterioration - high rainfall areas

a. Pasture deterioration - High rainfall areas - A farm at Karridale (near Augusta) exhibiting classic pasture deterioration symptoms was closely monitored throughout 1974. This farm has paddocks ranging from relatively newly sown pastures with a high clover percentage, few weeds and high dry matter production (resown 1973 and 1974), through to extremely poor pastures with as little as 3 % clover and a weed component of over 80% (resown 1970 and 1971)... b. Midland B competition studies (69Mt19) -This grazing trial was sown in 1969 to plots of pure Midland B, pure Woogenellup and to three mixtures of the two cultivars. Part of the area was cropped in 1971 but has been grazed with the rest of the trial since then... c. Midland B/Seaton Park /Yarloop/39313Y grazing trial (72Mt29) - In a non-waterlogged environment at Mt. Barker both Seaton Park and Midland B have successfully competed with Yarloop under grazing. Seaton Park has outperformed Midland B with both dry matter production and plant establishment, while 39313Y (Larissa) has produced far more dry matter than Yarloop late in the season although plant counts are very similar... It is proposed to crop part of each plot during 1975. Regeneration of each variety after cropping will be measured for at least one season

Clover scorch screening, root rot screening, bluegreen aphid screening, red legged earthmite screening experiments, evaluation of Medicago murex

Clover scorch screening. Root rot screening. Bluegreen aphid screening. Red legged earth mite screening experiments. Evaluation of Medicago murex

Cultivar evaluation in high rainfall areas

1. Trikkala Evaluation Trial 76MT3. A joint trial with D.A. Nicholas. The trial\u27s aim is to compare the competitive ability under grazing of Trikkala and Yarloop clover on a waterlogged new land site. The competitive ability to be measured in the presence and absence of clover scorch. (Kabatiella caulivora). 2. Pasture deterioration. Field experiments. Three trials established in 1975 to determine whether various cultivation techniques could control root rot and. subsequent pasture deterioration have now concluded. 3. Lucerne productivity and persistence. 4. Effects of saline irrigation water on pasture production. During the 1976/77 irrigation season the effects on pasture production of water from the Wellington (850mg/l of salt) and Stirling (260 mg/l) Dams was measured for the third year. Phytotron Experiments. TABLE 1. Trikkala evaluation trial seed set 1976/77. TABLE 2. Dry matter production (kg/ha) in 7 weeks Spring 1977. TABLE 3. Cultivation trials - 1977 plant density and dry matter production (7 weeks). Karridale, Walpole, Narrikup. TABLE 4. Susceptibility of sub clover varieties to root rot infection after four weeks growth. TABLE 5. Lucerne productivity and persistence. Trial 74E3 - Sheep, 74E4 - Cattle, 75AL30 - Cattle. TABLE 6. Pasture Yield and Clover Chloride concentration

Kabatiella caulivor, root rot resistance, bluegreen aphid, asessment of Medicago murex, clover establishment techniques

Kabatiella caulivora (clover scorch). In contrast to previous years where all overseas introductions and most crossbreds were tested for resistance to Kabatiella, only selected clovers are now being screened so as to reduce the number requiring testing to a manageable size. Root rot resistance screening. One hundred and seven clovers selected as low in formononetin, tolerant of clover scorch, mid to late season maturity, and reasonable winter vigour were tested at two sites for root rot resistance. Bluegreen aphid (BGA) resistance screening. Sub clover screening for bluegreen aphid resistance ranked from tolerant to susceptible (ratings at 49 days from commencement). Bluegreen Aphid resistance of some mid season crossbreds. Genetics of BGA resistance in sub clover. Table 5 shows the results obtained for parents and Fl progeny at the conclusion of the experiment. B.G.A. Genetic Study. Preliminary assessment of Medicago murex. Characteristics of Medicago murex at Perth/Augusta. Clover Establishment Techniques. Spring Clover Yield Kg/ha October 12, 1981. The effect of commencing Grazing at 6 weeks and 11 weeks on pasture establishment

Clover, Bluegreen aphid and Red legged mite screening, Medicago murex evaluation

Clover scorch: In spite of poor seasonal conditions, adequate levels of clover scorch developed in the test plots to readily identify susceptible clovers. Of the 333 introductions tested, 23% scored 3.0 or less indicating a high level of resistance. Bluegreen aphid screening: Two hundred and twenty four randomly selected subterranean clovers from all Western Mediterranean collections were tested for resistance to BGA in Nov/Dec of 1983. The susceptibility of annual legumes to Bluegreen aphid. Red legged earth mite screening: Results of two preliminary experiments to develop techniques for mass screening for RLEM resistance in subterranean clover were reported last year. Evaluation of Medicago murex: Seven small plot experiments were established in 1983 and results for that year have been reported previously. Regeneration density, nodulation, spring composition and seed yields were also recorded on these sites in 1984. Yields are shown in Table 2. The average yield of each site was different due to differences in grazing intensity, moisture stress during spring, and the presence of other species. Adjustments to the yields were made (as shown in the Table) and an average corrected yield for each variety was then calculated

Clover cultivar and trikkala evaluaton; Lucerne productivity and persistence; Pasture deterioration investigations.

Clover cultivar evaluation; high rainfall areas. Trikkala Yarloop evaluation. Lucerne productivity and persistence. 77BU1, 77D1, 77D4, 77ES31, 77ES32, 77ES33, 74E3

Evaluation of Late Maturing Clover Cultivars. Woogenellup Alternative Clovers. Selection for Bluegreen Aphid Resistance. Root Rot Resistance.

Evaluation of Late Maturing Clover Cultivars. Bacchus Marsh, Clare, Cyprus, Daliak, Denmark Dinninup, Dwalganup, Esperance, Geraldton, Harbinger, Karridale, Larisa, Meteora, Mt. Barker, Nangeela, Northam, Northcliffe, Nungarin, Pitman serradella, Plantagenet, Seaton Park, Tallarook, Tornfield, Trikkala, Yarloop, Woogenellup, 1. Evaluation of late maturing clover cultivars. Three trials established in 1977 and due to terminate in 1979 were continued into 1980 to obtain further data on the performance of the late yanninicum Meteora {39327YB). A full report on the performance of this variety in these trials was prepared for the Herbage Plant Liaison Committee and is reproduced below. Table 1 - Residual Hard Seed Percentage. 2. Woogenellup alternative evaluation. Two sites were sown in May 1980 to six crossbreds selected as possible replacements for Woogenellup. In each experiment Woogenellup and Esperance were sown as controls. Spring production figures were obtained from the Narrikup site but not from Esperance because of severe drought. Table 2 - Dry Matter Production Spring 1980 - Narrikup Yields in kg/ha (8 weeks\u27 growth). Table 3 - Seed Yield of Woogenellup Alternative Clovers Summer 1980/81 Yields in kg/ha. 3. Selection for bluegreen aphid resistance. During 1980 over 140 clover varieties were tested in the glasshouse for resistance to Bluegreen Aphid (B.G.A.) All commercial clover cultivars were tested both as seedlings and as vegetative plants and the results are presented in Table 4. Table 4 - Legume Screening for B.G.A. Resistance Comparison of seedling and vegetative plant screening 4. Root rot resistance testing In 1979 only two selections had less root rot than the resistance controls (Daliak and Dinninup) , but in 1980 nine selections were identified as being more resistant. Twenty-three selections had more root rot than the susceptible controls (Woogenellup and Mt. Barker) in 1979 and 22 in 1980. Some of the results for 1980 are shown in Table 5 together with the 1979 result for the control varieties. Table 5 - Root Rot Performance of Some Clover Selections at Scott River (1980) and Denmark (1979)