A study of heterosis, combining ability and heritability between two male sterile lines and ten inbred lines of Tagetes patula

Abstract

Two male sterile lines (Ms-1, Ms-2) and ten inbred lines (K3, K4, K5, K8, K13, K15, K17, K20, K30, K33) were crossed according to Comstock and Robinson's (in: Gowen (ed.) Heterosis, 1952) North Carolina Design II to estimate heterosis, combining ability, heritability and the phenotypic correlation coefficient for 11 ornamental characteristics of Tagetes patula. Twenty cross combinations and 12 parents were evaluated for 11 ornamental characteristics, in a randomized complete block design with three replications, in trials conducted during 2011 and 2012 at Huazhong Agricultural University, Wuhan, China. The results showed that the hybrid combinations displayed higher ornamental values and showed obvious heterosis over the male-parent for most of the ornamental traits evaluated. The male sterile line Ms-1 scored highly for general combining ability (GCA) with respect to the development of F 1 offspring with a dwarf and compact plant habit, abundant double petals, and extended period between the opening and wilting of individual inflorescences. The male sterile line Ms-2 scored highly for GCA with respect to the development of F 1 offspring with a large plant form and large flower size, as well as abundant flower numbers. The specific combining ability (SCA) of cross Ms-2 9 K20 was found to be high, with progeny showing high positive heterosis over the male parent and superior mean values for all ornamental traits, thereby indicating that this cross has the potential to function as a superior cultivar within commercial breeding programmes. Both GCA effects and SCA effects were found to be important for the performance of individual hybrid combinations, and no clear relationship between GCA and SCA was found for these T. patula lines. The ratio of r 2 GCA =r 2 SCA for individual characteristics revealed that the relative importance of GCA and SCA to progeny quality varied for different traits. Estimates of heritability showed that many of the quantitative ornamental traits of T. patula were highly heritable, and the traits of diameter of center disk and number of ray florets should readily be improved by selection. By contrast, environmental factors influenced markedly on the traits of plant height, crown size, number of days between opening and wilting of inflorescences and the maximum number of flowers present each day. Phenotypic correlation coefficient analysis showed that the various vegetative growth characteristics were closely related to one another and, more interestingly, significant phenotypic correlations were found between the growth of the vegetative and reproductive structures of T. patula.

Cross Compatibility Analysis to Identify Suitable Parents of Tagetes erecta and T. patula for Heterotic Hybrid Breeding

“…Tagetes patula, often called the French marigold, belongs to the genus Tagetes spp. The specie is one of the most important annual ornamental plants in commercial cultivation (Ai et al, 2015;Cicevan et al, 2016). The French marigold is different from the African marigold in many ornamental traits.…”

Transcriptomic Analysis of Differentially Expressed Genes during Flower Organ Development in Genetic Male Sterile and Male Fertile Tagetes erecta by Digital Gene-Expression Profiling

“…Plants with male sterility have been applied effectively and economically in plant breeding for pollination control, especially in Asteraceae family, which has the unique structure of terminal capitulum that contains hundreds of florets of two different types, ray florets in the periphery and disk florets in the center. Breeders are looking for the male sterile (MS) plants with defective anthers, and degenerated petals of ray and disc florets to save the expense on manual emasculation [ 1 , 2 ]. Tagetes erecta , a member of the Asteraceae family, is an important commercial plant used for ornamental, industrial and medicinal purposes [ 3 – 5 ].…”

Interspecific hybridization with African marigold (Tagetes erecta) can improve flower-related performance in French marigold (T. patula)

“…T. patula, popularly known as French marigold, is a sister species of African marigold. It may thrive in a variety of soil and climate conditions (Pan, 2014;Ai et al, 2015;He et al, 2006). Because of its short maintenance time, abundant blossoms, lengthy flowering period, inconspicuous residual flowers, and ease of cultivation and care, it is one of the most significant annual herbaceous flowers used as bedding plants (Cicevan et al, 2016).…”