Population structures and seasons affected flowering, pollination and reproductive outputs of sandalwood in Gunung Sewu, Java, Indonesia

Abstract

Ratnaningrum YWN, Indrioko S, Faridah E, Syahbudin A. 2018. Population structures and seasons affected flowering, pollination and reproductive outputs of sandalwood in Gunung Sewu, Java, Indonesia. Nusantara Bioscience 10: 12-26. Sandalwood was the origin to the south-eastern islands of Indonesia, but is recently occurred as new landraces in Gunung Sewu Geopark, Java, Indonesia. This study compared flowering and pollination, and their effect on reproductive outputs, among sandalwood populations in Gunung Sewu, during the dry and rainy season of 2016 flowering period. Flowering and pollination rate differed significantly between seasons but were similar among sites. Oppositely, reproductive outputs differed significantly among sites, but were similar between seasons. The rainy season produced more flowers and pollination. Pollination was less correlated to flowers abundance, but more affected by population size. The higher and cooler population visited more by Dipterans (31.8% to 32.6%) and Hymenopterans (28.2% to 30%), while the warmer, lower sites dominated by Lepidopterans (37.2% to 43%) and Dipterans (32.9% to 38.2%). Higher population received fewer visits, but more visitors diversity (28 families). In contrast, lower sites received more visits, but with less diversity (20 families). Most insect families were considered “Rare” and “Occasional”. However, pooled altogether, the whole families of Lepidopterans and Dipterans considered “Frequent” and “Effective”. The Hymenopterans considered “Frequent” and “Effective” at Nglanggeran and Wanagama. The Cicadellidae of Coleopterans, along with arachnids and grasshoppers, were considered robbers. All of the agents were diurnal. However, the time of activity was varied. Rainy season gained more flowers and visits, but in contrast, resulted in fewer fruits at all sites. Both flowers abundance and pollination were negatively correlated to the reproductive parameters. Populations might gain more flowers and visits, but the reproductive outputs were significantly lower. Particularly in the clonalized and lower heterozygosity populations, more flowers increased geitonogamy which may lead to inbreeding depression.

Floral structure and genetical differences of sandalwood variants in Gunung Sewu (Java, Indonesia), and its effects on breeding systems and reproductive ability

“…Sandalwood observed in this study is a yearly flowering perennial sub-shrub of semi-arid and tropical regions (Ratnaningrum et al 2016). Preliminary studies in this species found the dichogamy type, highly outcrossing rate and self-incompatibility Ratnaningrum et al 2016Ratnaningrum et al , 2017bRatnaningrum et al , 2018, even in some cases, partially self-compatibility has also been reported (Ratnaningrum et al , 2017a. In the study sites, sandalwood has preference to propagate vegetatively by producing root suckers, sprouting emerged from the horizontal roots.…”

“…Considering a rapid degradation of sandalwood population in its native in the eastern parts of Indonesia, the occurrence of new landraces in Gunung Sewu Geopark, a 1300 km 2 mountainous limestone zones in the central part of Java island, may provide a promising source for any of rehabilitation efforts. Our preliminary studies revealed that population with wider genetic base have higher outcrossing rate, genetic diversity and reproductive ability (Ratnaningrum et al , 2017a(Ratnaningrum et al , 2018. In contrary, the low genetic base, fragmentation and clonality may reduce genetic diversity and alter the mating system to be more inbred (Indrioko and Ratnaningrum 2015;Ratnaningrum et al , 2017a, inhibit gene flow (Ratnaningrum et al 2017a), and increase reproductive failure (Indrioko and Ratnaningrum 2015;Ratnaningrum et al 2017aRatnaningrum et al , 2018.…”

“…Our preliminary studies revealed that population with wider genetic base have higher outcrossing rate, genetic diversity and reproductive ability (Ratnaningrum et al , 2017a(Ratnaningrum et al , 2018. In contrary, the low genetic base, fragmentation and clonality may reduce genetic diversity and alter the mating system to be more inbred (Indrioko and Ratnaningrum 2015;Ratnaningrum et al , 2017a, inhibit gene flow (Ratnaningrum et al 2017a), and increase reproductive failure (Indrioko and Ratnaningrum 2015;Ratnaningrum et al 2017aRatnaningrum et al , 2018. Landraces in Gunung Sewu consist of three variants (OBF, refers to "orange big flower"; RBF, "red big flower"; and RSF, "red small flower", respectively) differed in floral structures (Syahbudin et al 2005;Arifriana et al 2017), flowering (Ratnaningrum et al 2017b) and pollination events (Fathin and Ratnaningrum 2018).…”

“…Reproductive failure might also occurred as a result of mating barriers due to the differences on floral structures and biology among individuals within population, that in turn lead to a mating incompatibility (Rughkla et al 2006;Barrett 2011;Tamla et al 2012;Gan et al 2013;Salisbury et al 2017;Yang et al 2017). In such cases, pollination barrier occurred due to the differences on the length of stylus and/or filament, structures of corolla, stigma-anthers position (Rughkla et al 2006;Fernandez et al 2009;Tamla et al 2012), pistil dysfunction, male sterility (Sindhu-Vereendra and Anantha-Padmanabha 1996; Warburton et al 2000) and/or flowering asynchrony (Ratnaningrum et al 2016(Ratnaningrum et al , 2017b(Ratnaningrum et al , 2018. Self-incompatibility due to self-mating in sandalwood has reported in Petir and Bejiharjo landraces, Gunung Sewu (Indrioko and Ratnaningrum 2015) and Western Australia (Warburton et al 2000).…”

“…Self-incompatibility due to self-mating in sandalwood has reported in Petir and Bejiharjo landraces, Gunung Sewu (Indrioko and Ratnaningrum 2015) and Western Australia (Warburton et al 2000). Whilst, mating barriers due to different floral structures has found in S. album in Gunung Sewu (Ratnaningrum et al 2018), S. lanceolatum and S. spicatum in Western Australia (Tamla et al 2012).…”