Agriculture Reference
In-Depth Information
100
80
Leafless panicles
60
40
Vegetative shoots
20
0
0
40
80
120
160
Days at 15/10°C after panicle emergence
Fig. 9.2.
Effect of post-panicle emergence temperature response to 15/10°C before
transfer to 30/25°C on 'Gui wei' litchi panicle development (after Menzel and
Simpson, 1991).
Leaves are arranged alternately, pinnately compound with two to fi ve
pairs of leafl ets arranged in opposite positions or slightly obliquely along the
rachis (Fig. 9.3). The leafl ets are elliptical to lanceolate, 2.5-6.4 cm wide,
7.6-17 cm long, and deep green. Young, emerging fl ushes range from pale
green to pinkish to a copperish red. Growth fl ushes can occur several times a
year and are vegetative fl ushes of several leaves in summer and can be fl oral
in winter. Vegetative fl ushing is encouraged immediately after harvest in
summer by fertilizing and irrigating (Fig. 9.1). The fl oral fl ush is a terminal
infl orescence. A close relationship exists between number of leaves associated
with a fl owering panicle and number of fruits on that panicle (Fig. 9.4). Hence,
a minimum number of two leaves per fruit is required.
The longan tree can grow to 20 m and has either a spreading or erect
habit. The compound longan leaves are around 25 cm long with 6-12 leafl ets,
alternate or nearly opposite, oblong, 5-15 cm long with blunt or pointed
ends (Fig. 9.5). The leaves are dark glossy green on the upper side and pale
green underneath.
Flowers
The small litchi fl owers are 3.0-6.0 mm in length when fully expanded (Fig.
9.3), and borne in profusion on leafl ess or leafy, well-branched terminal
panicles. In the northern hemisphere, appearance of panicles can begin
as early as November to as late as April, depending upon cultivar and
environmental conditions. Flowers are yellow-green or brownish-yellow,
apetalous with small valvate sepals (Fig. 9.3), a fl eshy disc and up to eight
stamens. Among the numerous, apetalous fl owers on the panicle, three sex
types are described for litchi. These sex types are designated Types I, II and III,
