AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA ISSN Print: 2151-7517, ISSN Online: 2151-7525, doi:10.5251/abjna.2010.1.6.1162.1168 © 2010, ScienceHuβ, http://www.scihub.org/ABJNA The performance of Amaranthus cruentus and Celosia argentea as affected by varying sowing depths F.O. Odeleye1* and A. O. Olufolaji 2 1Dept. of Crop Protection and Environmental Biology, University of Ibadan, Nigeria. 2National Horticultural Research Institute, Jericho, Idi-ishin, Ibadan,Nigeria *Corresponding author: [email protected] ABSTRACT Screen house trials were carried out to evaluate the optimum sowing depths of Amaranthus and Celosia at the National Horticultural Research Institute, Ibadan, Nigeria. Seeds of NHAc3 and ED82/1040A varieties of Amaranthus and local green and TLV8 of Celosia (chosen on the basis of maturity period) were sown at 0,1,2 and 3cm depths using split-split design in randomized blocks with 4 replications. Data were taken on % germination, seedling emergence and establishment indices. Results indicate that Celosia had a higher % seedling emergence than Amaranthus . However, Amaranthus grew significantly taller than Celosia at plant establishment. Highest number of seedlings emerged at 0 cm depth but plants had highest number of leaves and total fresh vegetable production at 1 cm sowing depth. The two crops sown at and 1 cm gave significantly higher root development index than other interactive effects. However, the highest shoot development index was obtained at 0cm depth. The study demonstrated a significant interaction of sowing depth x variety such that the varieties (irrespective of species) performed best at 1 cm depth. The early maturing variety in the crops also had higher vigour, germination and root and shoot development indices than the late maturing variety. Keywords: Sowing depth, shoot/root development indices, seedling emergence, Amaranthus, Celosia INTRODUCTION emergence is also influenced by the depth of sowing as small seeded crops like amaranths have limited Amaranthus cruentus and Celosia argentea are two food reserves to support germination and seedling leafy vegetable crops with wide acceptance in Nigeria emergence (Mayer and Polkajoff-Mayber, 1975). and worldwide. They provide cheap sources of This limitation often restricts the depth from which an vitamins minerals and proteins. The leaves are amaranth seedling could emerge. Webb, et al., consumed as vegetable whereas the seeds could be (1987) reported that seeding as deep as 2.5cm processed into snacks. The productivity of these should be practical in friable soils if seeding rates are crops is largely dependent on the cultural practices adjusted to compensate for reduced percent employed during their cultivation. Some of the emergence associated with depth of sowing. Mayer cultural practices employed during the cultivation of and Polkajoff-Mayber (1975) also reported that these crops in Nigeria include intercropping with emergence could be influenced by soil type since other crops like maize (Muoneke and Ndukwe, 2008; soil, strength has an important type of effect on the Awe and Abegunrin, 2009); fertilizer application ability of roots to penetrate into the soil especially (Zobolo,et al, 2008); weeding Ogunyemi et al., 2001 through clods or firmly structured layers. The rootlet ), disease and pest control (Lovisolo and Lisa,1979, must therefore develop a pressure to pierce the soil. Siddiqui and Alam, 1989) and depth of sowing The growing roots could develop a pressure up to 10 Seedling emergence and establishment has been bars. shown to be a function of size of the seed and the Depth of sowing is a cultural practice that may be depth of sowing during cultivation. Emergence is an particularly crucial for Amaranthus and Celosia since expression of a complex interaction of seed factors they have very small seeds. In okra with relatively including genotype, vigour, and soil factors acting at large seeds, Odeleye et al reported that planting or after the time of sowing. For example, evidence beyond 3cm depth led to reduced emergence, vigour showed the superiority of large carrot seeds over and yield. Effects of sowing depths have also been small ones in emergence and standard establishment reported in pigeon pea (Tayo, 1983); Corn (Gupta et (Jacobsohn and Globerson, 1980). Seedling Agric. Biol. J. N. Am., 2010, 1(6): 1162-1168 al 1983, Alessi and Power (1971), Soybean, Abrecht taken of the number of germinated seedlings for 1989, but the seeds of all these crops are much depth 0 and emerged seedlings for 1, 2 and 3cm bigger than those of Amaranthus and Celosia . depths of sowing up till 2 weeks and the percent Farmers usually mix the seeds of these crops with seedling establishment at 4 weeks. soil and broadcast. This practice usually expose the The experiment involved two varieties of Amaranthus seeds on the soil surface. This may adversely affect (NHA 3) and ED82/1040A) and two varieties of the germination and performance of these crops. It is C Celosia (TLV8 and Local green). The design was pertinent therefore to determine the optimum sowing split plot in randomized complete block design with 4 depth for Amaranthus and Celosia which was the replicates. objective of this study. RESULTS MATERIALS AND METHODS The percent seedling emergence was significantly Two trials were carried out to evaluate the optimum higher in Celosia than in Amaranthus. At plant depth of sowing of Amaranthus and Celosia at the establishment (4 weeks after sowing) Amaranthus greenhouse of National Horticultural Research grew significantly taller than Celosia. Among the Institute, Ibadan. Seeds of NHA 3 and ED82/1040A C sowing depth, seedling emergence was significantly varieties of Amaranthus and local green and TLV8 of different in the order 0cm > 1cm > 2cm > 3cm; while Celosia were sown at 0, 1, 2, and 3 cm depths. One the significant difference in the leaf area was in the hundred seeds were sown per depth per variety in 60 order 1cm > 0cm, 2cm > cm. the highest leaf area x 18 x 6cm nursery trays. production was recorded in Celosia sown at 1cm The planting medium was top soil mixed with cured depth, while the least occurred in Amaranthus sown poultry droppings in the ratio 4:1. Records were at 3cm depth (Table 1). Table 1: Mean values of the vegetable characters of A. cruentus and C. argentea at varying depths of sowing Treatment Emergence Stem height (cm2 Leaf number Leaf area (cm2 plant-1 plant-1 Celosia 52:19 7.45 7.58 64.02 Amaranthus 42.19 9.78 7.76 25.55 LSD (P=0.05) 6.89 1.17 0.88 7.92 Depth 0cm 61.56 8.43 7.45 30.94 1cm 53.75 8.92 8.12 42.05 2cm 42.50 9.20 8.30 26.67 3cm 30.94 7.91 6.84 19.00 LSD (P=0.05) 5.66 1.11 0.80 5.69 Depth x spp 0cm x Celosia 80.63 7.78 7.84 35.16 1cm x Celosia 50.63 7.29 7.64 48.19 2cm x Celosia 45.63 7.63 7.99 30.32 3cm x Celosia 31.88 7.08 6.85 22.42 0cm x Amaranthus 42.50 9.09 7.06 26.72 1cm x Amaranthus 56.88 10.55 8.60 36.85 2cm x Amaranthus 39.38 10.77 8.61 23.03 3cm x Amaranthus 30.00 8.73 6.83 15.59 LSD (P=0.05) 9.54 1.76 1.29 10.30 accumulated in the shoot to the weight of viable The total plant fresh weight was similar in both seeds sown was significantly better in Celosia than in Amaranthus and Celosia species, however total Amaranthus. The shoot development index was vegetable production was higher at 1cm depth than significantly different among the depths in the order at the other three sowing depths which had similar 0cm > 1cm > 2cm > 3cm. the highest shoot values. Both species sown at 1cm and 3cm gave the development index was similar in both species and highest and lowest total fresh vegetable production, was similar but significantly lower in 1, 2 and 3cm respectively Table 2. depths of sowing than in 0cm depth. Celosia at 0cm, Amaranthus at 0 and 1cm gave significantly higher The shoot development index which is an absolute figure and defined as the ratio of the dry matter 1163 Agric. Biol. J. N. Am., 2010, 1(6): 1162-1168 root development index than at the other interactive highest number of leaves were produced at sowing effects (Table 2). depths 2cm and 3cm, leaf area was in the order 1cm >2cm. 0cm > 3cm. Interaction showed that NHA Amaranthus cruentus: In this crop the % seedling C and ED82/1040A at 1cm depth were superior in leaf emergence was significantly higher in the early area production to all the other variety x sowing depth flowering NHA 3 than the late flowering ED82/1040A C interactions (able 3). The total plant fresh weight was (Table 3). The percent seedling emergence was similar in both varieties of Amaranthus but significantly different in the order 1cm > 2cm > 0cm > significantly different among the depth in the order 3cm. The variety x depth interaction indicated that 1cm > 2cm > 0cm > 3cm. At 4 week ED82/1040A at the highest seedling emergence occurred in NHA 3 C 1cm depth gave the highest fresh vegetable sown at 1cm, while the least emergence was production than all other variety x effects (Table 4). observed in ED82/10440A sown at 3cm depth (Table The shoot development index was highest at 1cm 3). The stem height per plant was similar in the two sowing depth and least at 0cm (surface) and 3cm varieties while sowing at 1cm and 2 cm depths gave sowing depths. Variety ED82/1040A gave the similar but significantly taller plants than sowing at highest shoot development index when sown at 1cm 0cm, and 3cm depths both of which gave similar and the least at 3cm (Table 4).