M. del Rio

Survey of safflower (Carthamus tinctorius L .)germplasm for variants in fatty acid composition and other seed characters

SummaryTwo hundred safflower accessions, originated in 37 countries, and multiplied in two environments, were evaluated for fatty acid composition of the seed oil and other seed characters. Overall mean values of stearic and palmitic acids were similar in both environments but differed for seed weight and oil content. Oleic and linoleic acids showed also similar overall mean content in both environments but some entries with intermediate contents of these acids displayed significant variation among environments. Oleic and linoleic acids showed a tremendous range of variation, from 3.1 to 90.60% and from 3.9 to 88.8%, respectively. The ranges of variation observed for stearic, oleic and linoleic acids indicate that all the reccessive genes, already discovered, controlling high content of these acids, st, ol and li, are present in the collection. Moreover, the upper values of oleic, ten points higher than the published values for the high oleic genotype olol, suggest than other genes controlling such levels may be present.

Transgressive segregation of erucic acid content in Brassica carinata A. Braun.

Abstract Two Ethiopian mustard (Brassica carinata A. Braun) lines with low (about 10%) and zero erucic acid (C22:1) have been obtained. The low C22:1 mutant line L-2890 was isolated after a chemical-mutagen treatment of C-101 seeds (about 40% C22:1). The zero C22:1 line L-25X-1 was obtained by interspecific crossing. Our objective was to determine the genetic control of low and zero C22:1 contents in these lines and the relationship between the loci controlling these traits. Reciprocal crosses between L-2890, L-25X-1 and high C22:1 lines, and between L-2890 and L-25X-1, were made. The F1, F2 and BC1 F1 generations were obtained. No maternal or cytoplasmic effects for C22:1 content were observed in any of the crosses. The analysis of the fatty acid composition in the segregating populations from the crosses of L-2890 with the high C22:1 lines C-101 and L-1630 indicated that the segregation patterns fitted a model of two alleles at two loci, M1 and M2, with partial (near complete) dominance for high concentration. The segregation patterns in the cross of the zero C22:1 line L-25X-1 with the high C22:1 line L-1630, were explained on the basis of two genes, E1 and E2, with additive gene action. The F1 and segregating generations of the crosses L-2890 × L-25X-1 showed a strong transgressive segregation with C22:1 values of up to 50.0%, four-fold higher than those of L-2890. The analyses of the F2, BC1F1 and F3 generations indicated that the combination of alleles at four loci, M1 and M2 in L-2890 and E1 and E2 in L-25X-1, controlled the transgressive segregation for C22:1. The proposed genotypes (C22:1 content) for each parent were as follows: L-2890 (10% C22:1) = m1m1m2m2E1E1E2E2; L-25X-1 (0% C22:1) = M1M1M2M2e1e1e2e2; and C-101 (45% C22:1) = M1M1M2M2E1E1E2E2.

Sericite clay as a raw material for the fabrication of whiteware bodies

Abstract The possibility was investigated of abtaining porcelain bodies using a sericitic clay, whose fundamental characteristics are to form a very reactive glassy phase, to have an exceptional firing range and a very fine grain size, and a tendency to produce bodies with a very high mullite content at low temperature. The second aim was to obtain porcelain bodies at low firing temperatures with a high flexural strength and large mullite content using only the above-mentioned clay, alumina and a small and constant amount of feldspar. To cover different porcelain types, both silicious and aluminous, eight compositions were formulated and fired between 1200°C and 1320°C and the technological properties, microstructures, phases, etc., were studied. For comparison with the results obtained with the new compositions, two industrial porcelain bodies were formulated and studied at the same time under the same conditions. The paper shows the possibility of obtaining porcelain bodies with much better properties than present industrial ones, and at the same time with a significant saving in the cost of raw materials.