Seed handling of specific forest tree species : Recalcitrant and intermediate seed

Abstract

Indonesia is a tropical country with an area of rain forests around 128 million ha. Forests have economic, social and environmental functions, therefore those functions must be sustained. Seeds are a very important part for maintaining the sustainability of forest functions, by providing good quality of seeds and seedlings. Nearly 70% of the seeds of forest plants in Indonesia are recalcitrant and intermediate, dominated by species of Dipterocarpaceae, Myrtaceae, Araucariaceae, and Verbenaceae. In general, the characteristics of the seeds can be divided into 3 groups based on their sensitivity of drying and storability, namely orthodox, recalcitrant and intermediates. The viability of orthodox seeds can be maintained for long storage periods in low temperatures, whereas recalcitrant seeds are difficult to store for long periods and loseitsviability in a short time. Intermediate seeds are in between of the two characters, that the viability can be kept for a longer time (generally less than 1 year) than recalcitrant seeds. The main problems for recalcitrant and intermediate seeds are their short life time and for some species, the flowering and fruiting periods do not occur every year, especially for the species of Dipterocarpacae. These problems makedifficult to get large quantities of high-quality seeds. Therefore, seed handling techniques of recalcitrant and intermediates seeds are urgently needed. A proper seed handling is the key to maintain the physical, physiological and genetic quality of seeds which should be carried out by involving several activities including techniques of seed production, seed testing, seed storage, and nursery technique.

Physical, biochemical, and Physiological changes on oil palm (Elaeis guineensis L. Jacq) seeds throughout short-term storage

“…Oil palm seeds are categorized as intermediate-type seeds [2] whose moisture content can be reduced to a certain level and stored at low temperatures. Yulianti et al [21] explained that although intermediate seeds can be stored for a relatively longer time than recalcitrant seeds, their storage duration is shorter than orthodox seeds. The authors further stated that intermediate seeds can be stored for less than 1 year.…”

An Insight into the Behaviour of Recalcitrant Seeds by Understanding Their Molecular Changes upon Desiccation and Low Temperature

“…Examples of crop plants that bear orthodox seeds are wheat (Triticum aestivum L.), cereal rye (Secale cereale L.), and legumes such as the common bean (Phaseolus vulgaris L.), rice (Oryza sativa), banana (Musa balbisiana), and guava (Psidium guineense) [2,[33][34][35]. Apart from their capability to retain viability when dried to a low water content of 2−5%, orthodox seeds can be also distinguished from recalcitrant seeds based on their size, which is relatively smaller than recalcitrant seeds, as shown in Figure 1 [36]. Rapeseed plants (Brassica napus oleifera L.) bear orthodox seeds, which include sizes ranged from 1.5-2 mm [37].…”

Variation in seed morpho-physiological traits of Nauclea orientalis L. in a seedling seed orchard and the effect of seed sortation on their physiological parameters

“…The establishment of progeny tests followed by selection, both individual selection within families and family selection, is needed to obtain seeds with superior genetic quality [5]. Apart from genetics, seed quality is also greatly influenced by its physical and physiological quality [16] which is the result of the seed handling process [17]. However, the physical and physiological qualities of seed are also influenced by the genetic character of the mother tree [18] so that it allows for variations in the physical and genetic characteristics of seeds between mother trees.…”