Sarhad J. Agric. Vol.25, No.2, 2009

PHENOLOY AND YIELD OF SWEET CORN LANDRACES INFLUENCED BY PLANTING DATES

ZAFAR HAYAT KHAN*, SHAD KHAN KHALIL*, SHAHEEN NIGAR**, IFTIKHAR H. KHALIL***, IKRAMUL HAQ*****, IFTIKHAR AHMAD*****, ASAD ALI**** and M. YASIR KHAN***

* Department of Agronomy, NWFP Agricultural University, Peshawar, Pakistan ** Institute of Development Studies, NWFP Agricultural University, Peshawar, Pakistan *** Department of Plant Breeding & Genetics, NWFP Agricultural University, Peshawar, Pakistan **** Department of Plant Pathology, NWFP Agricultural University, Peshawar, Pakistan ***** Department of Agricultural Extension Education & Communication, NWFP Agricultural University, Peshawar, Pakistan

ABSTRACT This study was conducted to determine the production potential and optimum sowing date for various landraces of sweet corn. The research was carried out at New Developmental Farm, NWFP Agricultural University Peshawar, Pakistan during 2007 crop season. Sowing dates were 25 April (D1), 25 May (D2), 16 June (D3), 26 July (D4) and 18 August (D5). Sweet corn landraces Mingora, Mansehra, Swabi, Parachinar and cv. Azam were used. All parameters were significantly affected by sowing dates, landraces and their interaction. Days to 50 % tasseling and 50 % silking decreased as the date of sowing was delayed from D1 to D5. Days to maturity decreased as the date of sowing was delayed from D1 to D3 and then increased again as sowing was delayed from D3 to D5. Sweet corn landrace Swabi produced maximum (17292 kg ha-1) biological yield from D1 sowing compared to minimum (7083 kg ha-1) produced by Parachinar on D5. Azam produced maximum grain yield (4097 kg ha-1) and harvest index (27.21 %) when sown on D4, where as minimum grain yield (621 kg ha-1) and harvest index (7.16 %) was observed for Parachinar and Mingora respectively on D5 sowing.

Key Words: Phenology, Yield, Landraces, Sweet Corn

Citation: Khan, Z.H., S.K. Khalil, S. Nigar, I.H. Khalil, Ikramul Haq, I, Ahmad, A. Ali and M.Y. Khan. 2009. Phenology and yield of sweet corn landraces influenced by planting dates. Sarhad J. Agric. 25(2): 153-157.

INTRODUCTION Sweet corn (Zea mays saccharata) is primarily grown in North America. However sweet corn consumption has considerably increased over the past 30 years worldwide. Sweet corn differs from field corn in terms of its genetic makeup rather than in its systematic or taxonomic characterization (Marshall, 1987). The pericarp and endosperm tissues of sweet corn are the primary products consumed. Sweet corn is produced for human consumption either as fresh or processed product. Before it ripe and dry – it has a sweeter taste than do other corn types because its endosperm contains sugar as well as starch. Sweet corn is grown for local markets in Azad Jammu Kashmir and several areas of NWFP.

Planting at proper time and selection of suitable varies are important components of cropping system. Significant effects of sowing dates on fresh ear yield, duration of tasseling, ear diameter, kernel numbers ear-1, fresh ear weight and husk ratio have been reported by Oktem et al. (2004). Earliest planting of corn is preferable because of utilization of the entire growing season, achieving physiological maturity before frost, and proper drying; thereby increasing profit through reduced drying costs (Joseph et al., 1999). Beside corn growth has been affected by planting date as reported by Swanson and Wilhelm (1996). Nafziger (1994) stated that yields increased from mid- April to late April planting dates, then declined as planting was delayed to late May. Ahmadi et al. (1993) investigated planting date and population combinations in four field experiments; and reported significant interaction between planting date and hybrid. Arif et al. (2001) concluded that planting methods, varieties and their interaction significantly affected cob length, number of grains cob-1, grain weight cob-1, biological yield and grain yield.

The present study was therefore initiated to study sweet corn landraces under different sowing dates for various parameters and to workout optimum planting date for Peshawar region.

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MATERIALS AND METHODS In order to study landraces of sweet corn under different planting dates, an experiment was carried out at New Developmental Farm, NWFP Agricultural University Peshawar, Pakistan during 2007. Sowing dates were 25 April, 25 May, 16 June, 26 July and 18 August while landraces were Mingora, Mansehra, Swabi, Parachinar and cv. Azam (check). The crop was planted in 4m × 3.6m plots having 6 rows, each 4m long. Treatments were replicated three times in randomized complete block design with split plot arrangements. Planting dates were allotted to main plots while landraces were maintained in sub-plots. Treatments were randomized in main and sub-plots. The crop was sown in 60cm spaced out rows with the help of hand hoe. Plant population of 120000 plants ha-1 was maintained by thinning. A basal dose of 120:70 N: P kg ha-1 was used. Urea and SSP were used as sources of N and P2O5, respectively.

Table I Monthly climate data during the growth period of sweet corn in 2007 in Peshawar Months Temperature (°C) Mean Relative Maximum Minimum Mean Humidity (%) April 34.20 16.20 25.20 55.38 May 36.06 19.88 27.97 49.61 June 40.12 24.71 32.42 49.35 July 36.71 25.90 31.31 64.73 August 37.41 26.48 31.95 65.77 September 35.13 23.37 29.26 66.72 October 31.53 14.59 23.06 46.88 November 26.67 10.20 18.44 73.60 December 22.63 6.74 14.69 68.22

Standard agronomical practices were followed throughout the growing season. The following observations were recorded during the course of study; i. Days to 50% tasseling ii. Days to 50% silking iii. Days to maturity iv. Grain yield v. Biological yield vi. Harvest index

Days to 50% tasseling and 50% silking were counted from sowing till 50% of the plants in each subplot produced tassels and silk, respectively. Days to maturity were counted from sowing till maturity. Biological yield was measured by harvesting two central rows of each sub-plot and weighing them. The data were then constructed into biological yield ha-1. Biological Yield of 2 rows Biological Yield (Kg/ha) = ×100,000 No. of rows × Row - Row distance × Row length

Sun dried plants were threshed to record grain yield and then converted in to grain yield ha-1, accordingly. Harvest index was calculated as follows:

Grain Yield Harvest Index (%) = ×100 Biological Yield

RESULTS AND DISCUSSION Statistical analysis of the data showed that, days to 50% tasseling (Table II) were significantly affected by sowing dates, landraces and their interaction. Maximum days to tasseling were observed in plots sown on D1 with landrace Parachinar, whereas Mingora was the earliest to tassel when planted on D5. These results showed a decrease in days to tasseling from April sowing to August sowing. This decrease may be due to higher temperature and humidity during later months which hasten plant growth and development. These results are in conformity with Daughtry et al., (1984) and Shaw (1988) who reported dependence of tasseling duration on temperature and variety. Shaw and Thom (1951) concluded that the period from emergence to tasseling was more variable than the others. They found a negative relationship between the length of period from planting to tasseling and average temperature. Sarhad J. Agric. Vol.25, No.2, 2009 155

Table II. Days to 50% tasseling for different landraces/varieties and sowing dates Sowing Landraces Means dates Azam Mingora Mansehra Swabi Parachinar 25th April 60 e 62 c 63 b 62 c 64 a 62 a 25th May 60 e 61 d 61 d 62 c 62 c 61 b 16th June 58 f 56 g 60 e 61 d 56 g 58 c 26th July 53 h 47 m 50 j 52 i 49 k 50 d 18th August 48 l 45n 47 m 49 k 47 m 47 e Means 56 b 54 c 56 b 57 a 56 b LSD for sowing dates at P<0.05 = 0.29 LSD for varieties at P<0.05 = 0.24 LSD value for interaction at P<0.05 = 0.53

Data on days to 50 % silking are presented in Table III. Sowing dates, landraces and their interaction showed significant effect on days to silking. Parachinar took maximum days to silking on April sowing (D1), whereas Mingora with August (D5) sowing took minimum days. Days to silking are related with tasseling and showed similar trend of decrease with later sowings.

Table III. Days to 50% silking for different landraces/varieties and sowing dates Sowing dates Landraces Means Azam Mingora Mansehra Swabi Parachinar th 25 April 66 d 67 c 68 b 68 b 69 a 68 a th 25 May 63 f 65 e 65 e 66 d 68 b 65 b th 16 June 62 g 60 h 62 g 62 g 63 f 62 c th 26 July 56 j 52 n 55 k 59 i 53 m 55 d th 18 August 53 m 49 p 52 n 54 l 51 o 52 e Means 60 c 59 d 60 c 62 a 61 b LSD for sowing dates at P<0.05 = 0.45 LSD for varieties at P<0.05 = 0.39 LSD value for interaction at P<0.05 = 0.86

Table IV reveals significant effects of sowing dates, landraces and their interaction on days to maturity. Maximum days to maturity were taken by Parachinar planted on D1 while Mingora took minimum days to maturity when planted on D4. Similar results are reported by Zaki et al., (1994) who reported decrease in days to maturity with delaying of sowing from 16 April to 16 June and then increase again as sowing was delayed from 16 July to 16 August.

Table IV. Days to maturity for different landraces/varieties and sowing dates Sowing dates Landraces Means Azam Mingora Mansehra Swabi Parachinar th 25 April 114 c 121 b 112 d 120 b 124 a 118 a th 25 May 94 i 100 h 105 g 101 h 107 f 101 c th 16 June 86 l 89 k 89 k 85 lm 91 j 88 e th 26 July 92 j 84 m 89 k 85 lm 95 i 89 d th 18 August 101 h 108 f 104 g 105 g 110 e 106 b Means 97 d 100 b 100 b 99 c 106 a

LSD for sowing dates at P<0.05 = 0.64 LSD for varieties at P<0.05 = 0.55 LSD value for interaction at P<0.05 = 1.24

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Biological yield was significantly affected by sowing dates and landraces (Table V). Maximum biological yield was recorded with April sowing of Swabi while Parachinar produced minimum biological yield with August sowing. In April sowing plants took maximum days to maturity and this extended growth and development period may be one of the reasons for higher biological yields. Possible climatological variables affecting growth and development of corn are temperature, moisture and relative humidity. These results are in conformity with Arif et al. (2001) who reported significant differences in biological yield due to varietal differences.

Table V. Biological yield (kg ha-1) for different landraces/varieties and sowing dates Sowing Landraces Means dates Azam Mingora Mansehra Swabi Parachinar th 25 April 13611±139d 16597±303 b 16597±139 b 17292±208 a 16111±139 b 16042 a th 25 May 8681±184 j 7847±184 k 9514±184 ghi 10139±184 g 7292±318 kl 8695 d th 16 June 7500±0 kl 9236±387 hij 11667±120 f 12569±139 e 9861±303gh 10167 c th 26 July 15069±387 c 13403±184 d 16528±593 b 13542±208 d 13958±208 d 14500 b th 18 August 7292±120 kl 9167±120 ij 8750±120 j 9305±178 hij 7083±0 l 8319 e Means 10431d 11250 b 12611 a 12569 a 10861 c LSD for sowing dates at P<0.05 = 354.30 LSD for varieties at P<0.05 = 309.90 LSD value for interaction at P<0.05 = 693 Standard deviation= 3463

Grain yield is the function of integrated effect of all individual yield components and interaction between the genetic makeup and plant environment during the growing period. Statistical analysis of the data revealed that grain yield of sweet corn was significantly affected by sowing dates, landraces and their interaction (Table VI). Azam gave maximum grain yield when planted in July (D4) while Parachinar gave minimum grain yield from August (D5) sowing. Proper growth and development conditions for July sowing may be resulted in higher grain yields. Shorter vegetative growth period for August sown sweet corn and then low temperature and incident solar radiation during grain filling stage may have resulted in lowest grain yield. Frost at later stages of plants growth may be another reason for lower yields. Grain yield decreased from April sowing to May sowing then increased to maximum in July and again decreased to minimum grain yield in August sowing. Similar results are reported by Herbek et al. (1986) showing decrease in grain yield when sowing delayed from late April to mid-May. Zaki et al., (1994) conformed above results presenting decrease in grain yield from April to May sowing and then increase in yield from June sowing. They reported lower grain yields from August sowing. Ahmadi et al. (1993) reported effects of planting date on yield. They further noted significant interaction between planting date and hybrid.

Table VI. Grains yield (kg ha-1) for different landraces/varieties and sowing dates Sowing dates Landraces Means Azam Mingora Mansehra Swabi Parachinar th 25 April 3676 b 1556 j 2141f 1832 h 1573 j 2156 b th 25 May 1817 h 945 m 1281 k 1373 k 855 n 1254 d th 16 June 1967 g 1146 l 1604 i 1779 hi 1148 l 1529 c th 26 July 4097 a 2388 e 2639 d 2781 c 2319 e 2845 a th 18 August 1039 m 728 o 743 o 804 no 621 p 787 e Means 2519 a 1353 c 1682 b 1714 b 1303 d LSD for sowing dates at P<0.05 = 38.54 LSD for varieties at P<0.05 = 42.94 LSD value for interaction at P<0.05 = 93.02 Standard deviation= 887

Harvest indices of sweet corn landraces were significantly affected by sowing dates, landraces and their interaction (Table VII). Highest value of harvest index (27.21 %) was noted for Azam sown on D4, whereas lowest (7.78 %) for Parachinar on D5 sowing. This may be due to favorable conditions for growth and development of Azam at D4. Harvest index is dependent on grain and biological yields of the crop and it changes with change in grain and biological yields.

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Table VII Harvest index (%) for different landraces/varieties and sowing dates Sowing dates Landraces Means Azam Mingora Mansehra Swabi Parachinar th 25 April 27.01±0.74a 9.38±0.19 kl 12.89±0.28 fgh 10.60±0.26 jk 9.76±0.15 kl 13.93 d th 25 May 23.85±1.77 b 12.05±0.20 hi 13.47±0.16 fg 13.55±0.18 fg 11.73±0.06 hij 14.93 c th 16 June 26.23±0.19 a 12.42±0.05 ghi 13.75±0.15 fg 14.16±0.15 f 11.64±0.13 hij 15.64 b th 26 July 27.21±0.58 a 17.83±0.34 d 16.01±0.57 e 20.55±0.39 c 16.62±0.28 de 19.64 a th 18 August 14.25±0.06 f 7.94±0.13 m 8.49±0.07 lm 8.63±0.06 lm 7.78±0.55 ij 9.42 e Means 23.71 a 11.92 c 12.92 b 13.50 b 11.51 c LSD for sowing dates at P<0.05 = 0.672 LSD for varieties at P<0.05 = 0.612 LSD value for interaction at P<0.05 = 1.37

CONCLUSION Sowing dates and landraces significantly affected different phenological and yield related parameters of sweet corn. For Peshawar region landrace collected from Swabi gave higher yields when sown on 26th July compared with other landraces of sweet corn.

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