Agriculture Reference
In-Depth Information
lary shoots and one or more inflorescence from the axil or leaves in three weeks.
Inflorescence segments, each bearing 4-5 florets, from four-week-old cultures of
nodal segments, were planted on MS + BAP (8.5 µM) + 2,4-D (4.5 µM) and after
three weeks individual ovaries were transferred to MS + 2,4-D (4.5 µM) + Glycine
(0.5 mg/l) + Proline (0.2 mg/l). In this treatment, 16 per cent of the ovaries devel-
oped a gynogenic seedling. After the gynogenic plants are transplanted in soil, out
of 20 plants examined, 12 showed haploid number of chromosome (2n = x = 14) and
the other eight were aneuploids with 13-17 chromosomes in their root tip cells.
4.7 Populus sp. (Family: Salicaceae)
Poplars form a very important part of basic forest biology and are economically im-
portant trees cultivated for their high wood quality that finds use in paper industry
and energy production. The genus Populus consist of more than 30species, occur-
ring throughout the forests of temperate and cold regions of northern hemisphere.
The species
P. ciliata
, the only native poplar of India, is endemic to the Himalayan
belt and has been an important tree for the forest breeders in India. In 1950, a large
number of exotic clones of
Populus
were introduced and grown in North India,
mainly, for increasing the wood availability for match and plywood industries. The
study of poplars is essential to complement the ever increasing knowledge database
of this important tree species.
First successful report on anther culture in
Populus
is by Wang et al. (
1975
),
who observed callus proliferation from pollen and subsequent formation of haploid
plants via organogenesis from the pollen-derived calli. Later, several reports were
published on production of pollen plantlets in anther cultures of poplar (Zhu et al.
1980
; Ho and Raj
1985
; Kim et al.
1986
; Mofidabadi et al.
1995
). Induction of
haploids via embryogenesis occurring from cultured anthers of
P. Maximowiczii
was obtained by Stoehr and Zsuffa (
1990
). The scientists applied cold pre-treatment
to the flower buds (at 4 °C for four days) prior to culture the anthers at uninucle-
ate stage of microspores, on MS medium containing 2,4-D (2.26 μM) and Kinetin
(0.46 μM). Globular calli were developed from anthers after 4-8 weeks of dark in-
cubation in the medium at 20 °C. When the anthers with globular calli were cultured
on MS medium supplemented with NAA (0.54 μM) and BAP (4.4 μM), microspore
division and embryoidal structures resembling globular-to-heart-shaped embryoids
were obtained. However, the embryoids germinated precociously without devel-
oping cotyledons. After transfer to MS medium with BAP (4.4 μM), adventitious
shoots developed mainly from the roots. Shoots were rooted on half strength MS
medium supplemented with NAA (0.13 μM). Out of 34 plants analyzed cytologi-
cally, 22 showed haploid chromosome number (n = 19), one was aneuploid and the
rest were diploids (Srivastava and Chaturvedi
2008
). Kiss et al. (
2001
) reported fur-
ther improvement in the rate of haploid plant regeneration by increasing the rate of
induction from the anthers and with sustained shoot regeneration frequency in five
