Effect of Different Planting Dates on Growth and Development of Gladiolus grandiflorus under the Ecological Conditions of Faisalabad, Pakistan

The present study was carried out to elucidate the effect of different sowing dates and temperature on growth, yield and quality of two important cultivars of Gladiolus grandiflorus L. Rose supreme and White prosperity .The results showed that different planting dates have significant effect on number of days taken by gladiolus corm to germinate. A significant superiority of T 1 5.5 days over T 2 with 9.10 days on all the treatments was observed. Among the treatments maximum sprouting percentage was recorded in T 2 with 94.66 % followed by T 3 82.19 % on all the treatments. The days to 6-leaves stage depict highly significant difference in variance of treatments, interactive effect of treatments and cultivars. The maximum plant height (115.33cm) was recorded in T 2 followed by T 3 with 111.04cm. Mean values of number of leaves indicated significant superiority of T 2 with 8.02 leaves and T 3 with 7.93 leaves on all other treatments. The maximum chlorophyll contents 71.60 were recorded in T 2 followed by T 3 with 67.65 on all the treatments. Spike length showed highly significant difference in variance of treatments, interactive effect of treatments and cultivars. The maximum number of florets (17.16) was recorded in T 2 followed by T 3 with 15.83 florets. Among the treatments to spiking, length of spike (cm), diameter of spike (cm), diameter of florets (mm), number of floret spike per plant, fresh weight of spike (g), dry weight of spike (g), corms parameters, diameter of corms (mm), weight of corms (g), number of cormels and weight of cormels (g) computed.


Introduction
Floriculture has emerged as a potential business in Pakistan. The  Date of planting plays an important role in regulating growth and quality of gladiolus.
Vegetative growth and quality of gladiolus is improved by proper planting times which also satisfy the consumer's demands 6  inflorescence and corms, and these are greatly affected by photoperiod 8 . Gladiolus as most common flowering plant, prefer a growing location in full sun for most of the day. Both the presence and absence of light greatly affects flower development. Flowering of gladiolus is controlled partially by day length provided temperatures are in the proper range.
The present research work was planned to investigate the growth and flowering of gladiolus in early and late growing season and to study its correlation with temperature under agro-ecological conditions of Faisalabad Pakistan and to establish a protocol for off-seasoning which is commercially feasible and easily adoptable with minimum capital investment. Growth parameters such as, days to germination, sprouting percentage, days to 6-leaves stage, plant height (cm), number of leaves and chlorophyll content (spad value) were determined. Flowering parameters such as, days to spiking, length of spike (cm), diameter of spike (cm), diameter of florets (mm), number of floret spike per plant, fresh weight of spike (g), dry weight of spike (g), corms parameters, diameter of corms (mm), weight of corms (g), number of cormels and weight of cormels (g)

Materials and Methods
were computed.

Statistical Analysis
The data was analyzed statistically by using analysis of variance technique and treatment means were compared in two factorial RCBD at 5% level of significance 9 . The relation of the different growth parameters and temperature were assessed through regression, co-relation analysis.

Soil analysis
Soil analysis showed that soil has normal electrical conductivity (EC) 2.05 dS m -1 and high pH (8.08). The amount of organic matter was also low (0.505 %). Potassium contents (195 mg kg -1 ) were in normal range while phosphorus contents (8.2 mg kg -1 ) were in critical ranges. The concentrations of zinc (1.2 mg kg -1 ) were in adequate amount while the content of nitrogen (10.12 %) was low (Table 1). Growth parameters

Days to Germination
The treatments comprising of different planting dates have a significant effect on number of days taken by gladiolus corm to germinate. The results indicated significant superiority of T 1 with only 5.5 days followed by T 2 with 9.10 days on all the treatments. T 6 occupy the bottom position with 20.80 days in the ranked order of treatments. T 1 plantation vanished after germination due to severe environmental conditions therefore only five treatments are discussed in following text (Table 2). Early germination at high temperature is also reported that elevated temperature within the appropriate range results in early sprouting of corms 8  in line with the findings of 10 who reported that temperature between 20˚C to 25˚C promoted germination to 97% in gladiolus.

Days to 6-Leaves Stage
Collected data regarding days to 6-leaves stage was subjected to statistical analysis and results conformity with the findings of 11 that plantings at higher temperature will take 37 to 45 days to reach 6leaves stage while low temperature would take 52 to 59 days (Fig 1).

Plant Height (cm)
Among the treatments, maximum plant height (115.33cm) was recorded in T 2 followed by T 3 (Fig 1).

Number of Leaves
All the observations were processed statistically and results obtained depict highly significant effects in variance of treatments whereas cultivars and variety x treatments interaction was found non- temperature. In this experiment highly positive correlation was observed between temperature and chlorophyll contents (Fig 1). high temperature is also reported by 11 who stated that gladiolus flowered more rapidly under warm temperatures regardless of photoperiod. In this experiment a strong correlation was observed between temperature and days to sprouting (Fig 2). The results are in line to the finding of 15  Nov. plantation. Shortening of gladiolus spike at low temperature is also reported by 15 . In this experiment highly positive correlation was observed between temperature and spike length (Fig 2).

Number of Florets spike -1
Among the treatments, maximun number of florets (17.16) was recorded in T 2 followed by T 3 with 15.83 florets. Least number of florets (12.74) was noticed in T 6 . Maximum temperature was recorded during plantation on 10 th Sep. and 25 th Sep. with 26.35˚C and 25.08˚C respectively while lowest temperature 15.85˚C was recorded during 10 th Nov. plantation.
The Increase in number of florets at high temperature is also reported by 16 who found more number of florets per plant, when planting was done during hot summer months. A strong correlation between temperature and number of florets was observed (Fig 2).

Fresh Weight of Spike (g)
The results revealed highly significant differences in fresh weight of spike among two cultivars of gladiolus. Variety × treatments interaction was found non-Significant and the effect of treatments was found significant. Means indicated superiority of T 2 in fresh weight of spike with 88.5 g followed by T 3 which got second best position with 87.5 g over rest of the treatments whereas, T 6 occupy bottom position with 67.5 g in the ranked order of treatments. Maximum temperature was recorded during plantation on

Effect of planting dates on Gladiolus grandiflorus
Adil et al., IJAVMS, Vol. 7, Issue 3, 2013: 94-107 recorded during 10 th Nov. plantation. A positive correlation between temperature and fresh weight of spike was observed (Fig 2). The results are in line with the findings of 17 who reported increased fresh weight of chrysanthemum flower at 17˚C as compared to 21˚C in a winter greenhouse experiment.

Dry Weight of Spike (g)
The results regarding effect of different planting dates on dry weight of spike of two cultivars of gladiolus indicated superiority of T 2 (10 th Sep.) in dry weight of spike with 28 g followed by T 3 (25 th Sep.) which got second best position with 27 g over rest of the treatments whereas, T 6 occupy bottom position with 17.5 g in the ranked order of treatments. Maximum temperature was recorded during plantation on 10 th Sep. and 25 th Sep. with 26.35˚C and 25.08˚C respectively while lowest temperature 15.85˚C was recorded during 10 th Nov. plantation. A positive correlation between temperature and dry weight of spike was observed (Fig 2). The results are in line with the findings of 18 who reported increased dry matter production at high temperature may be attributed to greater accumulation of photosynthates by vegetative parts in gladiolus.

Corm Diameter (cm)
Among the treatments maximum corm diameter (6.19 cm) was recorded on T 2 followed by T 6 with (5.96 cm). T 3 got the bottom position with 5.21 cm in the ranked order of treatments. Maximum temperature 21.6˚C was recorded during plantation done on 10 th Nov. followed by 10 th Sep. plantation with 19.4˚C while lowest temperature 14.75˚C was recorded during 25 th Sep. plantation. A positive correlation between temperature and corm diameter was also observed (Fig 2). The results are in line with the findings of 19 who reported increase in corm diameter at high temperature in part to the production of more photosynthates.

Corm weight (g)
The results of different planting dates on corm weight of two cultivars of gladiolus indicated significant superiority of T 2 with 63.82 g followed by T 6  and corm weight was also observed (Fig 2). The results are in line with the findings of 20 who reported increase in corm weight at high temperature and long day lengths.

Number of Cormels
Among the treatments maximum number of cormels (33.83) was recorded in T 6 followed by plantation. A positive correlation between temperature and number of cormels was also observed (Fig 2).
The results are in line with the findings of 21 who reported increase in gladiolus cormel production at slightly high temperature.
Finally it can be concluded that different planting dates and temperatures (weather difference) have a significant effect on the growth of gladiolus. Proper planting date not only reduce the production cost by reducing the crop time and thus increasing cost benefit ratio but also produce elite flowers with increased market value. The results of the experiment can also be used in scheduling and round the season production because all the sowing dates produce marketable size spikes.