SUMMARYSamples of seven wild populations of the predominantly selfing species Triticam longissimum were compared with samples of five populations of the closely related, but predominantly outcrossing species, T. speltoides. For most of the 36 quantitative characters which were examined, the differences between populations, the total variances of the populations and the mean within-family variances, were greater in the selfer than in the outbreeder. Theoretical models were analysed in an attempt to explain these results, using concepts of classical population genetics.

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MealHoldup and drainage characteristics have been determined for three jojoba meals of different nature and size distribution, using hexane and isopropanol as solvents. Density and viscosity properties of the oil-solvent solutions have been measured. The experimental information should be of value in the design of solvent extraction equipment for jojoba nuts.

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SUMMARYSupernumerary (B) chromosomes were found in two Out of three population samples of Triticum .cpeltoides from Turkey and further samples were studied from two Israeli populations previously reported to consist of a high frequency of B-carriers (Simchen et al., 1971). In the two Israeli populations, plants with B chromosomes have a lower frequency of terminal chiasmata and a higher frequency of interstitial chiasmata. This effect is proportional to the number of B chromosomes per plant, which varies in one population between 0 and 8 and in the other between 0 and 3. Evidence for selection against plants with a high number of Bs is presented.