Productivity of Maize Varieties intercropped with Cassava in Lafia and Makurdi Locations, Southern Guinea Savanna, Nigeria

Two experiments were conducted from 2015 to 2016 at the Teaching and Research Farm of the Federal University of Agriculture, Makurdi [Latitude 07o 45' 07o 50' N, Longtitude 08o 45'08o 50' E, elevation 98 m] in Benue State and the Research and Teaching Farm of the College of Agriculture, Lafia (Latitude 08.33N and Longitude 08.32E) in Nasarawa State, all located in Southern Guinea Savannah of Nigeria. The experiments sought to determine the performance of maize varieties when intercropped with cassava.The experiment was laid out as split-plot in randomized complete block design (RCBD) with three replications. The main plot treatment comprised of two cropping systems [sole cropping (maize, cassava) and row intercropping (maize + cassava)] while the sub-plot treatment was 3 maize varieties [Quality Protein Maize (QPM), Suwan 1-1 and the Local]. Each sub plot consisted of 5 ridges spaced 1m apart and 4m long and the net plot was the three middle ridges, 3m long. Intercropping severely depressed plant height at harvest, leaf area index at harvest, cob circumference, cob length, number of rows per cob, number of seeds per row, cob weight, grain yield and 100-ssed weight in Lafi and Makurdi. The highest grain yield of maize was produced when QPM was planted as a sole crop in Lafia (2.95t/ha) and Makurdi (2.99t/ha). However, values obtained from LEC and LER showed intercrop advantage. Similarly, intercropping decreased the growth and yield (plant height at harvest, root circumference, root length, number of marketable roots per plant, number of unmarketable roots per plant and root weight) of cassava in both locations. Intercropping cassava with Local maize produced the highest root weight in Lafia (8.50t/ha) and Makurdi (9.02t/ha) among the treatments intercropped. All LER and LEC values were above 1.0 and 0.25 respectively in both locations. Values obtained for competitive ratio showed that maize was mnore competitive than cassava probably due to its height advantage. Keywords— Maize Varieties, Lafia and Makurdi, RCBD.

same field (Andrews and Kassam, 1976).The success of any intercropping system depends mainly on selection of component crops (Vishwanatha et al., 2011). When two or more plants with different rooting systems, a different pattern of water and nutrient demand and a different above ground habit are planted together, water, nutrient and sunlight are used more effectively. One of the most important reasons to grow two or more crops together is the increase in productivity per unit of land (Preston, 2003).Information on the yield advantage and competitive abilities of maize/cassava intercropping systems in Southern Guinea Savanna of Nigeria is lacking. This study reported here sought to bridge this knowledge gap. The objectives of the study were: i.
To evaluate the suitability of three maize varieties for intercropping with cassava in Lafia and Makurdi. ii.
To determine the productivity of the maize/cassava intercropping in Lafia and Makurdi.  33N and Longitude 08.32E) in Nasarawa State, all located in Southern Guinea Savannah of Nigeria. The experiments sought to determine the performance of maize varieties when intercropped with cassava. Thirty core samples of soil were collected from different parts of the field from 0-30cm and bulked into a composite sample and used for the determination of physical and chemical properties of the soil (see Table 1) before planting. Both the physical and chemical analyses were done in the Soil Science Laboratory of the University of Agriculture, Makurdi. Measures of intercrop productivity was determined by using land equivalent ratio (LER) as described by Ofori and Stern (1987) and land equivalent coefficient (LEC) as illustrated by Adetiloye et al. (1983). Competitive ratio (CR) which indicates the number of times by which one component crop is more competitive than the other was calculated using the formula proposed by Willey et al. (1980). Standard procedures were followed in collecting all data and analysis was done using GENSTAT statistical software. Whenever differences between treatment means were significant, means were separated by Fishers Least Significant Difference at 5% level of probability.

Maize Component Plant Height at Harvest
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety on the plant height of maize at harvest was significant (P≤ 0.05) in Lafia and Makurdi. Data from Table 3 showed that irrespective of the cropping system, Suwan 1-1 gave the highest plant height of maize at harvest in both locations. The lowest plant height of maize at harvest was produced when Local maize was intercropped (Table 3). Sole cropping generally gave higher plant height of maize than intercropping in Lafia and Makurdi. Suwan 1-1 produced the highest plant height of maize in both locations among the varieties evaluated ( Table 2).

Leaf Area Index at Harvest
The leaf area index of maize at harvest as influenced by the main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety in Lafia and Makurdi was significant (P≤ 0.05). QPM produced the highest leaf area index of maize at harvest in both locations when it was planted as sole and the difference was significantly higher than that produced by any other treatment. The lowest leaf area index of maize at harvest was produced when Local maize was intercropped with cassava (Table 3). On a general note, sole cropping produced significantly higher leaf area index at harvest than intercropping in Lafia and Makurdi. QPM gave significantly higher leaf area index of maize than Suwan 1-1 which in turn produced significantly higher leaf area index than Local maize ( Table  2).

Cob Circumference
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety was significant (P≤ 0.05) on the cob circumference of maize in Lafia and Makurdi. Values obtained for cob circumference of maize in Makurdi were higher than those of Lafia. In both locations, sole QPM gave the highest cob circumference of maize and this was significantly higher than that produced by any other treatment except when Suwan 1-1 was planted as sole. Local maize gave the lowest cob circumference in Lafia and Makurdi when it was intercropped (Table 3). Sole cropping generally produced significantly higher cob circumference than intercropping in both location. QPM gave the highest cob circumference of maize in Lafia and Makurdi among the varieties but this was only significantly higher than Local maize (Table 2).

Cob Length
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety was significant (P≤ 0.05) on the cob length of maize in Lafia and Makurdi. Data presented in Table 3 showed that in Lafia, Suwan 1-1 produced the longest cob length when it was planted as sole but this was not so in Makurdi where Suwan 1-1 produced the highest cob length when it was intercropped. In Lafia, intercropped QPM gave the lowest cob weight of maize while in Makurdi, Local maize produced the shortest cob weight of maize (Table 3). Generally, sole cropping produced significantly higher cob length of maize than intercropping in Lafia and Makurdi. Irrespective of the location, Suwan 1-1 produced significantly higher cob length of maize (Table 2).

Number of Rows per Cob
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety was significant (P≤ 0.05) on the number of rows per cob of maize in Lafia and Makurdi. Data presented in Table 5 showed that in Lafia, QPM produced the same number of rows per cob and this represented the highest number of rows per cob in Lafia. In Makurdi, QPM produced the highest number of rows per cob when it was planted as sole but the difference was not significantly higher than that produced when Suwan 1-1 was also planted as sole crop (Table 5). Sole cropping gave significantly higher number of rows per cob than intercropping in both locations. QPM gave the highest number of rows per cob among the varieties evaluated but the difference was only significantly higher than Local maize ( Table 4).

Number of Seeds per Row
The number of seeds per row as influenced by the main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety in Lafia and Makurdi was significant (P≤ 0.05).
Regardless of the location, the highest number of seeds per row was produced when Suwan 1-1 was planted as a sole crop. In Makurdi, the number of seeds per row produced by sole Suwan 1-1 was not significantly different from that produced by sole QPM and intercropped Suwan 1-1. Intercropped Local maize gave the lowest number of seeds per row in both locations (Table 5). Sole cropping largely gave higher number of seeds per row than intercropping in all locations and the difference was significant. Suwan 1-1 produced the highest number of seeds per row among the varieties evaluated (Table 4).

Cob Weight
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize Cob weight values obtained from Makurdi were higher than those of Lafia. QPM produced the highest cob weight when it was planted as a sole crop in both locations but the difference was not significantly higher than that produced when Suwan 1-1 was planted as a sole crop. Local maize gave the lowest cob weight of maize when it was intercropped with cassava in Lafia and Makirdi (Table 5). Sole cropping produced significantly higher cob weight in both locations than intercropping. QPM produced the highest cob weight among the varieties evaluated but the difference was only significantly higher than that produced by Local maize (Table 4).

Grain Yield
The grain yield of maize at harvest as influenced by the main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety in Lafia and Makurdi was significant (P≤ 0.05). Data presented in Table 5 revealed that Makurdi location produced higher grain yield values than Lafia location. In both locations, QPM gave the highest grain yield of maize when it was planted as sole but this was not significantly different from that produced when Suwan 1-1 was planted as sown and when QPM was intercropped (Table 5). Sole cropping produced significantly higher grain yield of maize than intercropping in all locations. Irrespective of the location, QPM gave the highest grain yield of maize but this was only significantly higher than that produced by Local maize (Table 4).

100-Seed Weight
The main effect of cropping system and maize variety as well as the interaction effects of cropping system x maize variety was significant (P≤ 0.05) on 100-seed weight of maize in Lafia and Makurdi. Data presented in Table 5 showed that in Lafia, Local maize gave the highest 100-seed weight of maize when it was planted as a sole crop but this was not so in Lafia where Suwan 1-1 gave the highest 100-seed weight of maize when it was planted as a sole crop. In Lafia, Local maize gave the lowest 100-seed weight of maize when it was intercropped while intercropped Suwan 1-1 gave the lowest 100-seed weight in Makurdi (Table 5). Sole cropping generally gave higher 100-seed weight of maize than intercropping in Lafia and Makurdi. Among the maize varieties evaluated, Local maize gave the highest 100-seed weight in Lafia and Makurdi (Table 4).  (Table 6).

Root Circumference
The root circumference of cassava as influenced by the main effect of cropping system and maize variety was significant (P≤ 0.05) in Lafia and Makurdi. Irrespective of the location, sole cassava produced the highest root circumference and this was significantly higher than that produced by any other treatment. Cassava intercropped with Local maize and cassava intercropped with Suwan 1-1 gave the highest and lowest root circumference of cassava in both locations respectively (Table 6).

Root Length
The root length of maize as influenced by the effect of cropping system and maize variety was significant (P≤ 0.05) in Lafia and Makurdi. In all locations, sole cassava produced significantly higher root length than cassava intercropped with Local maize which in turn gave significantly higher root length than cassava intercropped with QPM and Suwan 1-1 respectively (Table 6).

Number of Marketable Roots per Plant
Cropping system and maize varieties had significant (P≤ 0.05) effect on the number of marketable roots per plant in Lafia and Makurdi. Regardless of the location, sole cassava produced the highest number of marketable roots per plant and this was significantly higher than that produced by any other treatment. In all locations, no significant difference was observed among the cassava treatments intercropped ( Table 7).

Number of Unmarketable Roots per Plant
The number of unmarketable roots per plant as influenced by the effect of cropping system and maize variety was significant (P≤ 0.05) in Lafia and Makurdi. In both locations, sole cropping had the highest number of unmarketable roots per plant and the difference was significant. No significant difference was observed on the number of marketable per plant among the treatments intercropped (Table 7). The root weight of maize as influenced by the effect of cropping system and maize variety was significant (P≤ 0.05) in Lafia and Makurdi. Sole cassava produced significantly higher root weight in both locations and this was significantly higher than that produced by any other treatment. Cassava intercropped with Local maize gave the highest root weight of cassava among the treatments intercropped and the difference was significant (Table 7).  (Table 8).

IV. DISCUSSION
The depression in plant height at harvest, leaf area index at harvest, cob circumference, cob length, number of rows per cob, number of seeds per row, cob weight, grain yield and 100-seed weight of maize as compared to sole crop resulted from inter-specific competition. Egbe and Adeyemo (2006) had also reported reduction in growth and yield of some component crops in mixtures. These authors opined that inter-specific competition for light, nutrients, water, air and other growth resources often resulted in depressed yields of the intercrop components. LER values were greater than unity in all treatments in both locations, indicating the advantage of intercropping over sole stands in regard to use of environmental growth resources. All LEC values were above 0.25 in Lafia and Makurdi. This further indicates that all intercropping combinations were better in resource use efficiency compared to growing the two crops separately. Adetiloye et al. (1983) stated that the minimum expected production before a yield advantage is obtained in a two-crop mixture is an LEC greater than 0.25 (Egbe et al., 2010). The highest LER and LEC in both locations was obtained when Local maize was intercropped with cassava. Intercropping thus, can be the most realistic cropping system to increase crop productivity in Lafia and Makurdi environments. Maize was the more dominant component of the maize/cassava intercropping systems, probably because of its height advantage. Fujita and Ofosu-Budu (1996)stated that the non-legume growth is severely suppressed due to depression of photosynthesis through decreases in irradiance.

V. CONCLUSION
Intercropping severely depressed plant height at harvest, leaf area index at harvest, cob circumference, cob length, number of rows per cob, number of seeds per row, cob weight, grain yield and 100-ssed weight in Lafi and Makurdi. In both locations, Suwan 1-1 generally produced the highest plant height at harvest, cob length and number of seeds per row. QPM gave the highest leaf area index at harvest, cob circumference, number of rows per cob, cob weight and grain yield in Lafia and Makurdi. Suwan 1-1 produced the highest 100-seed weight of maize in Lafia while Local maize gave the highest 100-seed weight of maize in Makurdi. Intercropping also decreased the growth and yield (plant height at harvest, root circumference, root length, number of marketable roots per plant, number of unmarketable roots per plant and root weight) of cassava in both locations. All LER and LEC values were above 1.0 and 0.25 respectively in both locations. Maize had higher competitive ratio values than cassava.