Introduction

Maize (Zea mays L) is one of the important crops grown in North Eastern Himalayan (NEH) region of India. The maize landraces of NEH region have extensive variability for plant, tassel, ear and kernel characteristics (Nass et al., 1993; Singode et al., 2011). The primitive group of maize comprised of several races of popcorn, which had differentiated at various altitudes and under diverse conditions, was distributed throughout the eastern Himalayan region. These genetic resources could enable development of cultivars not only with improved productivity but also with enhanced quality, biotic and abiotic stress tolerance. Many studies have emphasized that phenotypic and phenological information based on agro-morphological descriptors continues to be the first step for the assessment, description and classification of germplasm collections to enhance their use in maize breeding (Nass et al., 1993; Brandolini and Brandolini, 2001; Prasanna and Sharma, 2005; Sharma et al., 2010; Wasala et al., 2013; Kumar et al., 2015). Therefore, the characterization of collections from NEH region for favourable traits/alleles is urgently required for their use in breeding. Further it is also important to know about the performance of these landraces in the environment similar to their adaptation and outside to their habitat and identify the collection performing well outside their habitat. This will facilitate evaluation of widely adapted collection in other suitable areas to derive trait specific genetic stock and inbred lines to be utilized in maize improvement programme. Therefore, the present study was undertaken to collect the specific landraces from NEH region and to characterize and evaluate them for yield performances in their own natural habitat and outside their habitat.

1 Results

1.1 Collection of maize germplasm

NEH region is one of the strategic areas for collection of primitive material. The Nagaland area of NEH region was less explored based on the gap analysis of explorations conducted so far, hence survey was executed to collect 58 accessions from existing diversity at farmers field and farm store. In Nagaland, it is locally known as Seko, Sako, Metata, Mikreta (Phek district); Ongjuk, Ongchuk (Longleng district); Kholakithi (Zunheboto district); Cheng-hanger, Songton-Jeshou in (Tuensang district) and Tsungro (Wokha district) by local tribes. The maize cultivars of this area had specific features of sweet corn type (Mikreta, Onglik), sticky type (Seko, Isesu, Tesu, Tsungro) and pop corn type (Kholithi). The popcorn types are grown in small scale mainly to sell in local market. The collected accessions were very diverse in cob size (small, 8-10 cm, medium, 15-20 cm and long, 20-25 cm), grain colour (white, red, orange, yellow, orange-yellow, maroon, violet, black), shank colour (white, pink, violet), ear shape (short & bold, thin & long, conical) with flint, dent and semi-flint types, rows per cob (10-12), tip filled grains, number of cobs (1-3 cobs/plant), sticky and non sticky types (Figure 1). The young cobs of collection KC/S/I-22 were used as vegetable types; KC/S/I-19 and KC/S/I-35 as popcorn; KC/S/I-15 was used for making local biscuits known as Nyakmokan. Thus the collected material has the potential for developing trait specific genetic stock with specialty features like sweet type, baby corn type, pop corn and sticky type.

Figure 1 Variability in maize ears and kernels collected from Nagaland state of NEH region

1.2 Evaluation of maize collection

Analysis of variance (ANOVA) revealed significant genotypic variation for all the traits at Delhi and Shillong location. The frequency distribution of qualitative traits (Figure 2) were analyzed which revealed that majority of collections had dark green leaves (58%), droopy leaf orientation (58%), medium leaf width (67%) and regular kernel row arrangement (56%). For grain colour, theses collections comprised of equal proportion of white and orange (25%) followed by white cap (19%), variegated (15%) and red and yellow (6%) and mottled (2%). Regarding other grain parameters, most of the collections had round texture (67%), indented shape (50%) and medium grain size (73%). At Delhi location, the average value of days to tassel was 56 with range of 39 to 68 days whereas days to silk ranged from 46 to 74 days (Table 1). Based on coefficient of variance, collections were diverse for plant height (21.13%), ear height (31.43%), number of ears per plant (34.70%), ear length (22.61%), number of kernels per row (25.47%) and yield per plant (56.05%). The collections with high seed weight were KC/S/R-9 and KC/S/I-26 with more than 27.20 g 100 grain weight. The collections with prolific nature were KC/S/R-10 with mean ears per plant (1.6), KC/S/I-22(1.6), KC/S/I-44 (1.6), KC/S/I-55 (1.6), KC/S/I-21 (3.2) and KC/S/I-28 (3.6) (Table 2). The tallest collection was KC/S/R-3with plant height of 278 cm and ear height of 202 cm. The yield per plant varied from 24.56 to 104.49 g. At Shillong location, the mean value of days to tassel was 66.68 with range of 50 to 73 days whereas days to silk ranged from 51 to 76 days. Based on coefficient of variation, collections were diverse for ear height (26.56%), number of kernels per row (26.41%), grain weight (20.85%), kernel rows (34.80%) and yield per plant (34.35%). KC/S/I-14, KC/S/I-22, KC/S/I-44, KC/S/I-55, KC/S/I-58 (Table 2) were identified as promising accessions for prolificacy which was also observed during collection. The maximum plant height of 384 cm was recorded in collection KC/S/I-32. The collection KC/S/I-72 from Wokha had maximum ear length (24.40 cm). The collection KC/S/I-67 was early maturing, medium statured with multi-cob nature and KC/S/R-3 and KC/S/R-6 were promising for ear length.

Table 1 Descriptive statistics of maize collections evaluated at Delhi and Shillong

Table 2 Promising collections identified based on their performance at Delhi and Shillong

Figure 2 Frequency distribution of leaf and kernel characteristics in maize collections

2 Discussion

Undertaking exploration in the potential, rich and diverse area is very important for accumulation of variability in plant breeding research. In India, introduction of maize is considered to be the contribution of Columbus after 1492. He brought it from West Indies to Southern Spain in 1493 and introduced corn in Europe, followed by multiple introductions in later period to continent of Asia (Brandolini, 1970; Brandolini and Brandolini, 2001). However, due to primitive nature (hermaphrodite, pop corn, prolific, etc.) of maize in NEH region, Dhawan (1964) considered it having Indian centre of origin. Stonor and Anderson (1949) have reported distinctive varieties of maize-popcorn widely cultivated by primitive Nagas. The ethnological and linguistic evidence also suggested its Pre-Columbian introduction. Thus, NEH region is one of the strategic areas for collection of primitive material. The Nagaland area of NEH region was less explored based on the gap analysis of explorations conducted so far, hence survey was executed to collect 58 accessions from existing diversity at farmers’ field and farm store. The ample variability was collected from traditional maize populations of this region as displayed by large range of morphological variation with sufficient diversity in height, ear, kernel parameters, etc. This study also indicated that true potential expression of the agronomic traits can be realized at environment similar to their natural habitat. However, characterization and evaluation can be carried out in different environments to identify the promising accessions under natural environment as well as outside the natural environments. Singode et al. (2009) also identified promising accessions from NEH region for yield related traits at Delhi and/or Hyderabad locations. Thus, the study clearly demonstrated that despite environment-specific adaptations, many of the accessions (KC/S/R-3 and KC/S/R-6 for ear length; KC/S/I-22 for ears per plant; KC/S/R-11 for grain weight) are capable of showing high adaptability in different location (North Western Plain zone of India) other than their natural habitat. These collections with adapted performance could be utilized for diversifying the pools and deriving inbred lines with diverse specific features.

3 Material and Methods

Explorations for collection of indigenous diversity of maize from Nagaland were conductedduring October-November 2011 under a special drive to NEH region (Table 3). Fifty eight accessions from Nagaland were collected following proper sampling procedure. The altitude of collection varied from 696 m above sea level (Lanye, Phek; Nagaland) to 2 077 m above sea level (Reku, Phek; Nagaland). These accessions were evaluated in Augmented Block Design at NBPGR, New Delhi and NBPGR Regional Station, Umiam, Shillong during Kharif 2012 and 2013 with four checks HM-4, HQPM-1, Vivek-17 and Pusa Composite 3. The location Umiam was located at 1 000 m elevation, in rainfed, acid alfisol conditions (pH 5.2). The experimental field coordinates were 26ºN latitude and 92ºE longitude with annual temperature ranged between 6℃ and 29℃ and average rainfall ranged between 2 300 and 2 500 mm. The Delhi location had sandy loam soil with 7.8 pH. The experimental farm is situated at latitude of 28°40’ N and longitude of 77°12’ E and an altitude of 228.6 meters above the mean sea level (Arabian Sea). The mean annual rainfall of Delhi is 650 mm and with more than 80% rainfall during the south-west monsoon season (July-September) with mean annual evaporation of 850 mm and annual temperature ranges between 12℃ and 32℃. The data were recorded for agro-morphological descriptors as per the minimal descriptors and descriptor’s states developed by ICAR-NBPGR (Mahajan et al., 2000). The agronomic characters included days to tassel, days to silk, plant height(cm), ear height(cm), ear length(cm), ear diameter(cm), number of kernel rows per ear, number of kernels per row, days to maturity, number of ears per plant, 100 grain weight (g) and grain yield per plant (g). Agronomic traits were recorded on ten randomly selected competitive plants per plot. Qualitative traits were recorded using different descriptor states as: Leaf colour: 1.Dark green, 2.Green, 3.Light green, 4.Yellowish green; Leaf orientation: 1.Erect, 2.Drooping; Leaf width: 3.Narrow, 5.Medium, 7.Broad; Kernel row arrangement: 1.Regular, 2.Irregular, 3.Straight, 4.Spiral; Grain colour: 1.White, 2.Yellow, 3.Purple, 4.Variegated, 5.Brown, 6.Orange, 7.Mottled, 8.White cap, 9.Red; Grain texture: 1.Flat, 2.Beaked, 3.Round; Grain shape: 1.Shrunken, 2.Round, 3.Indented, 4.Pointed; Grain size: 3.Small, 5.medium, 7. Bold. The mean values for various yield-related traits were computed for each of the locations and were statistically analyzed vis-à-vis the checks using least squares method, for identification of promising accessions. The quantitative traits were further analysed for various statistical parameters viz. mean, range, variances, etc. and qualitative traits for frequency distribution. All the statistical analyses were done using SAS 9.3 and JMP12 software.

Table 3 Locality details of maize collection from Nagaland along with specific features

Authors’ Contributions

Jyoti Kumari- Data recording, analysis and interpretation, manuscript writing; Ashok Kumar- Planning of experiment and manuscript writing; K C Bhatt- Exploration, A K Mishra- Planning of experiment , T P Singh-data recording and R K Sharma-data recording and field management.

Acknowledgements

We sincerely thank all the farming communities across the NEH region who have been conserving the landraces and the Director, ICAR-NBPGR for providing infrastructure facility and support for carrying out this study.

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