2 research outputs found
Carotenoid Biosynthesis Changes in Five Red Pepper (Capsicum annuum L.) Cultivars during Ripening. Cultivar Selection for Breeding
Changes in the biosynthesis of individual carotenoid pigments have been investigated during fruit
ripening of five cultivars of red pepper (Capsicum annuum L.): Mana, Numex, Belrubi, Delfin, and
Negral (a chlorophyll-retaining mutant when ripe). The study was carried out throughout the
ripening process, and with special emphasis on the ripe stage, to discover possible differences between
cultivars and to characterize these by their carotenoid pattern and content for selecting the best
varieties for breeding programs. Ripening fruit of the five cultivars showed the typical and
characteristic pattern of carotenoid biosynthesis for the Capsicum genus. In the five cultivars, lutein
and neoxanthin, both characteristic chloroplast pigments, decreased in concentration with ripening
and eventually disappeared. â-Carotene, antheraxanthin, and violaxanthin increased in concentration,
and other pigments were biosynthesized de novo: zeaxanthin, â-cryptoxanthin, capsanthin,
capsorubin, capsanthin-5,6-epoxide, and cucurbitaxanthin A. A pool of zeaxanthin stands out of
the rest of pigment during ripening, which reveals the importance of this pigment as a branching
point in the carotenoid biosynthesis in Capsicum. Quantitatively, Negral cultivar showed the highest
increase in total carotenoid content (48.39-fold), followed by Mana and Delfin with 38.03- and 36.8-
fold, respectively, and by Belrubi and Numex with 28.03- and 23.48-fold, respectively. In all the red
varieties, there was an inverse relationship between total carotenoid content and the red to yellow
isochromic pigment fraction ratio (R/Y) and the capsanthin-to-zeaxanthin ratio (Caps/Zeax). This
seems to be related to the carotenogenic capacity of the cultivar, and thus selection and breeding
should not only seek a higher total carotenoid content but also attempt to increase these ratios. In
the present study, the cultivar Mana had the highest total carotenoid content (13 208 mg/kg dwt),
but the lowest R/Y (1.25) and Caps/Zeax (3.38) ratios, which are therefore the parameters to improve.
The cultivar Negral had a high carotenoid content (8797 mg/kg dwt) and high R/Y and Caps/Zeax
ratios and could be used for transfer of these characters in direct crosses with the cultivar Mana.
The cultivar Numex had the highest Caps/Zeax ratio (7.17) and is thus an ideal progenitor for this
character.The authors
express their sincere gratitude to CICYT (Spanish Government)
for supporting this research project, ALI97-0352.Peer reviewe