Effect of starter nitrogen on yield and yield components of chickpea (Cicer arietinum L.) at Dokri, Larkana

Nitrogen (N) fixing capacity of legumes varies greatly among species and due to soil conditions. Poor soil conditions may cause yield reduction of chickpea as a result of limited biological N fixation. A field experiment was conducted to evaluate impact of starter N levels on growth and yield of chickpea. Study was planned with four levels of starter N (0, 15, 30 and 45 kg N ha) with three replications at Research Area, Agronomy Department, Rice Research Institute, Dokri during 2014-15 and 2015-16. The variety DG-92 was used in the experiment. Results show that plant height, number of pods per plant, seed index and seed yield were significantly improved with the various levels of starter N. The results of correlation coefficient in 2014-2015 and 20152016 years were positive and significant correlations of seed yield with majority traits.


Introduction
In Pakistan chickpea (Cicer arietinum L.) is an important food legume crop grown in rabi (winter) season.It is an economical source of proteins, carbohydrates, oil, minerals and vitamins, therefore serve as integral component of diet, especially for poor [1,2].It is also used in preparation of variety of condiments, soups, snacks and sweets [3].Chickpea is adaptable to diverse agro-climatic conditions and grown in the subtropics to arid and semi-arid regions [4].It is predominantly grown in cool, dry periods on receding soil moisture, however it is sensitive to alkalinity, salinity and water logging [5].Chickpea is generally cultivated as barani or rainfed crop.
Being a multipurpose crop; it is used as food, feed and industrial purpose, its demand is continuously increasing [6].Although origin of chickpea is controversial, however, it is thought to be originated from western Asia, from where it spread to Europe and in more recently introduced in tropical Africa, Australia and central and southern America [7].South Asian countries produce more than two-third of global chickpea production.In addition to South Asian subcontinent it is also grown in West Asia, Australia North and East Africa, and North America [8].Botanically chickpea is of two types, desi (microsperma) mainly grown for its nutritious seeds, and kabuli (macrosperma) grown to provide salad and vegetable mixes [9].In Pakistan it covers an area of around 9.6 million hectares and during 2014-2015; the total annual production of chickpea is 4.84 million tones, with an average yield of 487 kg ha -1 , against the production of 3.99 million tons during 2013- Therefore optimum N fertilization level is important to maximize chickpea yield and profitability.The present study was performed to determine growth and yield of chickpea crop to varying levels of starter N fertilizer under agro-climatic conditions of Dokri, Sindh, Pakistan.

Materials and methods
Field experiment was performed at the Research Area of Agronomy Section, Rice Research Institute Dokri, Larkana, Sindh, Pakistan, during 2014-15 and 2015-16 using.Chickpea cultivar DG-92 was exposed to four levels of Nitrogen (N) including N0 = (Control) 0 kg N ha -1 , N1 = 15 kg N ha -1 , N2 = 30 kg N ha -1 and N3 = 45 kg N ha -1 .The research was arranged in randomized complete block design (RCBD) with three replications.Chickpea plants were sown on experimental plot of net area of 7.2 m2 (L×W=4×1.8m) with P×P and R×R distances of 15cm and, 30cm, with six rows and 160 plants per plot.Soil of experimental site was N deficient and high (8.3)pH.Under different N treatment complete N, as urea, was applied as single dose at the time of seed bed preparation.Standard and uniform plant protection measures and agronomic practices were performed throughout the growing season to avoid any unwanted stress, except N levels.The observations were made based on randomly selected and averages of five plants were used each experimental unit, which were further averaged for treatments means used for statistical analysis.Data on various traits including plant height, seeds per pod, branches per plant, pods per plant, seed index and seed yield were recorded.
Plant height was recorded from surface of ground to top tip of leaves.Number branches per plant, pods per plant and seeds per pod were recorded by counting branches, pods and seeds of each plant separately and then averaged from each replication.After separating yield, five samples of 100 seeds were picked at random from each replication, and then weight was recorded.Twenty plants were selected from each experimental plot.Calculate the value by unit formulae and then converted to kg ha -

Correlation
Plant height showed significantly positive correlation with no. of branches per plant and no of pods per plant (Table 3).No of pods per plant also show the positive correlation with no of branches per plant and seed index.Seed yield is correlated with growth and yield parameters.It show positive correlation with plant height, no. of pods per plant, no of branches per plant and seed index during both the year.

Conclusion
Increasing nitrogen application were seen to result in significant increase in plant height, number of pods per plant, seed weight and seed yield during both experimental years.However non-significant influence of nitrogen levels was observed for number of pods and branched per plant.Highest level of nitrogen (45 kg N ha -1 ) produced tallest chickpea plants.Although application of nitrogen at 30 kg ha -1 produced maximum values of number of seed per pod, number of pods per plant, 100-seed weight and seed yield, however, these were statistically at par with the values produced at nitrogen rate of 45 kg ha -1 during both experimental years.These results suggest that nitrogen fertilizer application at 30 kg ha -1 as starter can be helpful in improving growth and yield of chickpea under agroclimatic conditions of Dokri.

30]. Results Effect of nitrogen on plant height
1(Calculated the seed yield of 20 plants and then divided by 20.The obtained value was multiplied with standard plant population.Calculate the data and then averaged from each replication.The data collected were analyzed with one way ANOVA by MSTATC.For treatment mean discrimination LSD test was applied at 0.05 probability level [