Cytological and Hybridization Studies in Three Cultivars of Tuberose (<i>Polianthes tuberosa</i> L.)

Abstract

Three cultivars of tuberose (Polianthes tuberosa L.), one having spikes with single type of flowers (Single), another with double type of flowers (Double) and the third with single flowers and variegated leaves (Variegated) had somatic chromosome number of 2n=60 and karyotypes comprising 10 long and 50 short chromosomes. The three cultivars, and hybrids of Single Double' and Variegated Single showed regular meiosis with the chromosomes paired into 30 bivalents at metaphase I (M I). These observations suggest that flower doubling and leaf variegation in tuberose have arisen due to gene mutations and do not necessarily involve changes in chromosome number or structure. Self-and cross-pollination studies revealed that Single was self-incompatible, whereas Variegated was self-compatible and Single Variegated and Single Double crosses were also compatible. However, fruit and seed set and percent seed germination varied among compatible combinations. Self-incompatibility in Single was gametophytic in nature with the pollen tubes getting inhibited in the style. Intervarietal hybrids showed useful variation in inflorescence and floral characters, some hybrids having larger spikes and more flowers/spike than either of the parents.

Ovarian Incompatibility in Tuberose (Polianthes Tuberosa L.) Cultivars and Breeding Lines

“…Pod set observed from the cultivars upon sel ng indicates their compatibility. The results derived supports the ndings of Karihaloo (2019) and Uma and Gowda (2000) that the tuberose variety Variegated is self-compatible. Apart from that, the other single-type tuberose lines like IIHR-6, Arka Nirantara, Arka Shringar were also found to be self-compatible with the highest seed set percentage upon self-pollination.…”

“…Florescence microscopic study on the pollen-pistil interaction indicated the presence of 'gametophytic self-incompatibility' in operation as reported by Karihaloo (2019); Ranchana and Kannan (2016) in tuberose. Stylar inhibitions were also reported by Ghosh and Shivanna (1980) in Linum grandi orum, Karihaloo (2019) in tuberose and Shimizu and Okada (2000) in Arabidopsis.…”

“…Florescence microscopic study on the pollen-pistil interaction indicated the presence of 'gametophytic self-incompatibility' in operation as reported by Karihaloo (2019); Ranchana and Kannan (2016) in tuberose. Stylar inhibitions were also reported by Ghosh and Shivanna (1980) in Linum grandi orum, Karihaloo (2019) in tuberose and Shimizu and Okada (2000) in Arabidopsis. However, the observation of pollen tube germination, growth and entry through the style and into the ovule in other cultivars raises the possibility that negative pollen tube stylar interactions may be triggered in the late-acting self-incompatibility (LSI) species even though selfed pollen tubes continue to grow and enter the ovule for fertilization (Sage et al1999).…”

“…Tuberose possesses the characters of self-incompatibility and dichogamy, thereby preventing the fruit set upon sel ng (Shen et al, 1986;Seetharamu, 1993;Uma, 1990). Earlier studies on tuberose also stated that the seedlessness in tuberose, especially single owered cultivars is due to sterility (Joshi and Pantulu 1940), at present found to be owing to self-incompatibility (Shen et al, 1986 andKarihaloo, 2019).…”

Influence of Different Pulsing Solutions on Postharvest Life of Tuberose (Polianthes tuberosa L.) cv. Prajwal

“…It is one of the most popular and fragrant cut flowers grown in India as well as worldwide [3]. For single-stemmed tuberose, the basic chromosome number is 2n=60, whereas the chromosome number of double-flowered species have ranged from 2n=50 to 2n=54, 60 and 120 [4,5].…”