Restoration of pseudo-self-compatibility (PSC) in derivatives of a high-PSC × no-PSC cross in Nemesia strumosa Benth
SummaryMean PSC increased following each generation of recurrent selection in F1, F2 and F3Nemesia strumosa families derived from a cross of a 100% PSC plant to an unrelated 0% PSC plant. The first 100% PSC individuals occurred in the F4. Populations derived through sib pollination tended to have higher PSC means than lines derived through self pollination. One F3 family showed a three-fold higher PSC level when pollinated in the green-house than when pollinated in the growth chamber, while another F3 family similarly pollinated showed no change in PSC.
THE INHERITANCE OF MODIFIERS CONFERRING SELF‐FERTILITY IN THE PARTIALLY SELF‐INCOMPATIBLE PERENNIAL, CAMPANULA RAPUNCULOIDES L. (CAMPANULACEAE)
Abstract The role of partial self‐incompatibility in plant breeding system evolution has received little attention. Here, we examine the genetic basis of modifiers conferring self‐fertility in the creeping bellflower, Campanula rapunculoides L. (Campanulaceae), a partially self‐incompatible herb. A survey of 35 individuals from two natural populations indicates that 45% of them are strongly self‐incompatible, 40% intermediately self‐incompatible, and 15% weakly self‐incompatible and that some plants show a strong breakdown in self‐incompatibility over floral age. We generated 101 F1 families by random crossing among 31 parental plants and estimated the heritability of self‐fertility in day 1 and day 4 female‐phase flowers, the genetic correlation between day 1 and day 4 self‐fertility, and the coefficient of additive genetic variance of self‐fertility. We use linear regression and data from additional crosses to examine whether there are significant maternal effects in the expression of self‐fertility. We use Fain's test to determine if a major gene influences self‐fertility and, finding no evidence, use data from additional crosses on an F2 generation to estimate the mean number and dominance of genes conferring self‐fertility. These analyses indicate that the heritability (h2) of self‐fertility is 0.24 in day 1 female‐phase flowers and 0.44 in day 4 flowers, self‐fertility is primarily additive but shows some recessive effects, and self‐fertility is estimated to be controlled by four genetic factors. In addition, we have evidence that there may be maternal effects for self‐fertility, especially for weakly self‐incompatible plants. The significance of these results in the context of mating system evolution is discussed.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.