An approach for understanding the heredity of two quality traits (head color and tightness) in globe artichoke (Cynara scolymus L.)

Abstract

The inheritance of head color and tightness in globe artichoke was studied utilizing crosses between inbreed lines and between clones and self-pollinated clones from different genetic origins. These genetic materials were sowed in a completely randomized design with 20 plants per plot and genotype. Globe artichoke heads were classified into three colors (purple-green, purple and green) and three head tightness types (compact, fairly compact and soft) and the segregating ratios for these traits tested in each offspring using the chi-square test. Crosses between green and purple inbreed lines produced only purple-green heads but F 2 generation segregated at a purple-green:purple:green ratio of 9:3:4. The self-pollinated compact head clones produced a compact head:fairly compact head:soft head ratio of 12:3:1. The remaining crosses between lines and among clones and backcrosses verified these ratios. These results suggest that two loci with a simple recessive epistasis are involved in the inheritance of head color and that two loci with simple dominant epistasis are involved in the expression of the different head tightness types. The inheritance models proposed here could be helpful in predicting the appearance of artichoke heads if breeders need to obtain hybrid seeds for a desirable phenotype.

Morphology and SSR fingerprinting of newly developed Cynara cardunculus genotypes exploitable as ornamentals

“…The current genetic model for capitulum colour assumes the presence of two dominant genes, P and U (Cravero et al 2005): P_ allows anthocyanin production, resulting in purple bracts, while pp inhibits anthocyanin production resulting in green bracts; U_ results in an uneven distribution of anthocyanin pigments encoded by P, while uu results in an even distribution of pigment in the presence of P. Among the two F 1 populations it was possible to identify the predicted three classes of capitulum colouration (uneven purple, even purple, and green) segregating overall in the expected digenic ratio of 9:4:3 (Table 2). Superimposed on this pattern was a gradation in capitulum colour, along with streaks of different colour intensity, suggesting the existence of pigmentation modifier genes.…”

“…The main capitulum is invariably the largest. The immature capitula are polymorphic with respect to size and shape; some develop spiny outer bracts of various shades of green, and which later during development may turn purple (Cravero et al 2005;Pochard et al 1969). The mature capitulum can be white or violet.…”

“…The highly heterozygotic nature of the species produces a wide range of phenotypes, especially among progeny of crosses between the different taxa (Cravero et al 2005;Foury 1969;Lopez-Anido et al 1998;Mauromicale and Ierna 2000).…”

New genetic maps for globe artichoke and wild cardoon and their alignment with an SSR-based consensus map

“…At the genetic level therefore, we propose that the wild cardoon accession was spsp/sp Leaf sp Leaf and "Est" was Spsp/ Sp Leaf sp Leaf . With respect to head color, Cravero et al (2005) showed that within globe artichoke, two independent genes act epistatically to determine the trait; in the absence of dominant alleles at P the inflorescence bracts remain green (pp), while the genotype P-Udevelops purple-green bracts and P-uu uniformly purple bracts. The segregation for head color observed in the present mapping population was consistent with homozygosity composition in both parents at locus P, which determines the presence/absence of anthocyanic pigments (pp in "Wild" and PP in "Est"), while "Wild" was Uu and "Est" was uu; suggesting that the second locus, which determinates anthocyanin distribution, segregated.…”

“…Up to now, the mode of inheritance of only a few traits (earliness, color, spininess and tightness of the head) has been investigated in detail (Pécaut 1993;López Anido et al 1998;Mauromicale and Ierna 2000;Cravero et al 2005;Lanteri et al 2006;Portis et al 2012). The development of a genetic linkage map simplifies the genetic analysis of trait variation, particularly for those traits which are polygenically inherited.…”