Growth, flowering and cut flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 at different planting densities

Growth, flowering and flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 planted at densities of 44, 56, 70, 83 and 104 plants/m2 were evaluated. Stem diameter, leaf number, total leaf area, and overall plant fresh weight were reduced by 16, 7, 36 and 25%, respectively, but the leaf area index was increased by 50% at the highest planting density (104 plants/m2) as compared to the lowest density (44 plants/m2). Time taken to showing colour and harvesting, which was calculated from the beginning of short day, was delayed by high planting density. Measurement on the spray diameter showed a clear reduction at 83 plants/m2, and this improved the spray form. The length of flower stalks and vase life were not affected. There was marked reduction in the number of flower stalks as well as flower number at high densities (83 and 104 plants/m2). Generally, the cultivar (V720) used in this study can be planted at high density (83 plants/m2) under lowland condition and able to produce the premium grade flowers

Adventitious rooting in microcuttings of selected indigenous landscape trees of Malaysia

Rooting performance in microcuttings of five indigenous and one exotic landscape tree species was evaluated in a 60 days period. Rate of rooting varied greatly among species as Ilex cymosa, Tabebuia heterophylla and Agalaia korthalsii reached 100% rooting at 24, 42 and 48 days after insertion into the rooting medium followed by Lepisanthes rubiginosa and Hopea odorata species (95 & 80% rooting at 60 days, respectively). The poorest rooting ability (30% rooting at 60 days) was shown by Aporusa globifera and was first noticed at 30 days. Results of Ilex cymosa species for adventitious root induction per microcutting was markedly different from other species and it produced the highest number of adventitious roots (14.07 roots/microcutting). A. korthalsii generated the fewer, but the heaviest roots compared to I. cymosa. Rooting ability of microcuttings was highly correlated with its number of leaves produced during rooting (r = 0.869-0.981) as well as, with regenerative shoot length of the mother plants (r = 0.690-0.954). Regenerative leaf growth of mother plants and the rooting of their microcuttings was species-specific suggesting that developing association between the two parameters is difficult

Defoliation of chrysanthemum (Chrysanthemum morifolium Ramat) cv. Reagan Sunny for improved flowering and cut flower quality

The effects of different levels of defoliation i.e. 0 (control), 20, 40, 60 and 80% at visible floral bud stage on growth, flowering and cut flower quality of chrysanthemum (Chrysanthemum morifolium) cv. Reagan Sunny were investigated. Plant height was only reduced by 5% at the highest level of defoliation, whereas the stem diameter was not affected. The time of floral bud break (showing colour), was delayed as level of defoliation increased. However, time of floral bud break within a plant was more synchronised. The spray diameter was reduced and vase life was increased by defoliation up to 60%. Both contributed to better cut flower quality. Other quality parameters such as flower size and stem diameter were not markedly affected. Total fresh and dry weights were linearly decreased with level of defoliation. There was a change in dry matter distribution, in which more dry matter was partitioned to the structural parts i.e. the stems and flower stalks as level of defoliation increased. There was no change on dry matter partitioning to flowers by defoliation. Defoliation at 60% can be the compromised level for cv. Reagan Sunny grown under high temperature environment

Kesan gelembung udara dan auksin bagi penginduksian akar pada tunas arundina graminifolia dalam sistem rendaman berterusan tertutup

Arundina graminifolia atau orkid buluh adalah orkid yang hidup di atas tanah, tahan panas dan penyakit, mudah dijaga, berbunga sepanjang tahun dan sangat sesuai untuk dijadikan tanaman landskap di kawasan terbuka. Kebiasaannya, A. graminifolia dibiak melalui pembahagian rumpun dan kultur tisu. Kadar pembiakan daripada kaedah ini adalah sangat rendah dan mengambil masa yang lama untuk memperbanyakkan bahan tanaman. Penggunaan sistem rendaman berterusan tertutup (CPIS) telah berjaya mempercepatkan penginduksian mata tunas A. graminifolia. Namun, penginduksian akar mengambil masa yang agak lama iaitu melebihi tiga bulan. Oleh yang demikian, kajian ini bertujuan untuk menambahbaik sistem CPIS dengan menambah gelembung udara bagi mempercepatkan penginduksian akar pada tunas A. graminifolia. Seterusnya, penggunaan auksin asid naftalenasetik (NAA) dan asid indol-3-butirik (IBA) bagi meningkatkan peratus pengakaran pada tunas A. graminifolia turut dijalankan. Kehadiran gelembung udara di dalam sistem CPIS menunjukkan terdapat peningkatan yang signifikan untuk kelebaran, ketinggian dan kerenggangan mata tunas berbanding dengan CPIS tanpa kehadiran gelembung udara. Tunas yang terhasil dalam sistem CPIS dengan kehadiran gelembung udara juga mampu menghasilkan akar (10% tunas yang berakar) berbanding dengan sistem CPIS tanpa kehadiran gelembung udara yang langsung tidak menghasilkan akar. Penginduksian akar pada tunas A. graminifolia menggunakan IBA dan NAA dengan kepekatan 0, 0.5, 1.0 dan 1.5 ppm menunjukkan perbezaan yang signifikan berbanding kawalan. Penggunaan hormon NAA dengan kepekatan yang semakin meningkat telah meningkatkan purata panjang akar, namun memberi kesan sebaliknya diperhatikan pada rawatan IBA. Kesimpulannya, sistem CPIS dengan kehadiran gelembung udara berserta hormon NAA 1.5 ppm mampu menginduksi dan meningkatkan peratus pengakaran A. graminifolia dengan lebih cepat

Studies on the effectiveness of acute gamma and ion beam irradiation in generating flower colour mutation for Chrysanthemum morifolium

Chrysanthemum morifolium is an important temperate cut flower and potted plant for Malaysian local market and exporter. Considering chrysanthemum as a popular vegetatively propagated ornamental plant, induce mutations for breeding purposes are more beneficial. Several of physical mutagens have been used in mutation breeding including x-rays, gamma rays and ion beams. Gamma rays and ion beams are from two different linear energy transfer (LET) which are low and high, respectively. The objective of this study was to compare the effectiveness of acute gamma and ion beam irradiation in generating flower colour mutations on nodal explants of Chrysanthemum morifolium cv. ‘Reagan Red’. The nodal explants were irradiated with acute gamma (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 Gy) and ion beam (0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy). The optimal dose for in vitro shoot regeneration using acute gamma was in the range of 10 to 15.0Gy and for ion beam was between 3.5 to 4.0Gy. Relative biological effectiveness for ion beam was found 3.75 higher than the acute gamma. The regenerated plantlets were planted in the greenhouse at MARDI, Cameron Highland for morphological screening. The highest frequency of flower colour mutation for acute gamma was 77.8% whilst for ion beam were between 42.3 to 58.3%

Effect of ontogenic age on root and shoot development of Tabebuia heterophylla cuttings propagated in soilless culture

A study was conducted to evaluate the root and shoot development in cuttings of Tabebuia heterophyllataken from varying ages of stock plants (1, 6, 18, 36 and 60 months). Cuttings obtained from the mother plants were rooted on perlite in saturated propagation chambers for 60 days. Generations of new roots and their subsequent growth, and the growth of new leaves from the cutting were reduced exponentially as the age of the stock plants increases, following a decay curve of y=Ae-bx.. In contrast, accumulation of leaf dry weight was highest in cuttings taken from six months old stock plants as explained by a modified Hoerl function of y=A*b(1/x)*x-c. The ability of juvenile cuttings to form roots was easier compared with older cuttings, and hence produces a larger root ball, these cuttings are expected to have a higher ability to survive

Vol.33 No2

Growth, flowering and cut flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 at different planting densities [Pertumbuhan, pembungaan dan kualiti keratan bunga kekwa jenis spray (Chrysanthemum morifolium Ramat) kultivar V720 pada kepadatan yang berbeza] S. Ab. Kahar* and T.M.M. Mahmud** Key words: chrysanthemum, density, growth, flowering, quality Abstract Growth, flowering and flower quality of spray chrysanthemum (Chrysanthemum morifolium Ramat) cv. V720 planted at densities of 44, 56, 70, 83 and 104 plants/m 2 were evaluated. Stem diameter, leaf number, total leaf area, and overall plant fresh weight were reduced by 16, 7, 36 and 25%, respectively, but the leaf area index was increased by 50% at the highest planting density (104 plants/m 2 ) as compared to the lowest density (44 plants/m 2 ). Time taken to showing colour and harvesting, which was calculated from the beginning of short day, was delayed by high planting density. Measurement on the spray diameter showed a clear reduction at 83 plants/m 2 , and this improved the spray form. The length of flower stalks and vase life were not affected. There was marked reduction in the number of flower stalks as well as flower number at high densities (83 and 104 plants/m 2 ). Generally, the cultivar (V720) used in this study can be planted at high density (83 plants/m 2 ) under lowland condition and able to produce the premium grade flowers