Days to flowering
Mung bean is one of the warm climate legumes, it requires cool air and low humidity during the flowering period. The flowering time of the pure lines obtained by pure line selection of mung bean lines obtained from Turkey are presented in Table 1. The flowering period of 25 pure lines and registered mung bean cultivars varied between 70.0 and 89.0 days. Among the pure lines, the shortest flowering time was 70.0 days in line 07G01-17 and the longest flowering time was 88.7 days in line 70S01-9. The latest flowering was determined in Jade-AU variety (89.0 days) among the lines and varieties used in the study. The average flowering time of the lines and cultivars was determined as 80.2 days and 19 of the 25 mung bean lines flowered in less than this period (Table 1). This shows that there are promising lines for the variety among the existing lines.
Previous multi-environment studies have demonstrated that flowering time in mung bean is highly influenced by both genetic background and environmental conditions. For example,
Cancı and Toker (2005) observed a wide range of 20-76 days under the Mediterranean climate of Antalya, with a high heritability estimate (88%), indicating strong genetic control of this trait. Similarly,
Karaman and Kaya (2020) reported flowering times of 83.4-120.4 days in 2017 and 84-120 days under the conditions of Isparta, further supporting the presence of substantial genetic variability across environments.
The variation observed in our study is consistent with these findings and highlights the responsiveness of mung bean genotypes to environmental stimuli. Importantly, the documented high heritability suggests that flowering time can be effectively manipulated through selection, making it a valuable trait for breeding programs. Early or optimally timed flowering is particularly advantageous when developing high yielding recombinant lines adapted to contrasting environments.
50% Pod formation
In breeding studies of legume crops, traits such as earliness, flowering time, pod tying time and vegetation duration are positively correlated with seed emergence time. In the present study, pod setting time of different mung bean pure lines and cultivars varied between 80.0 - 103.0 days (Table 1). The earliest pod setting was determined in Partow cultivar with line 50N01-16, followed by lines 27S08-1 (82 days), 27S08-2 (85 days), 79M01-1 (85 days), 79M02-1 (85 days) and 79M02-8 (85 days). Jade-AU, another registered variety, had a later pod setting time (except 70S01-9) than the lines obtained from our country. The latest pod setting time was determined in line 70S01-9.
The mean pod setting time of the evaluated lines varied significantly. This variability is consistent with reports showing that pod-setting time in mung bean is shaped by both genotype and environmental conditions (
Begum et al. 2013). Reproductive traits such as flowering and pod initiation are known to respond strongly to temperature, moisture and humidity (
Akbay et al. 2020) and previous studies have recorded first pod-setting times ranging from 47 to 68 days (
Pekşen et al. 2015). The variation observed in our study indicates a useful level of genetic diversity, suggesting that earlier pod-setting lines may serve as promising parents for developing high-yielding recombinants and for selection in multi-environment breeding programs.
Vegetation duration
The vegetation period of mung bean varieties and pure lines varied between 120.0-153.0 days. The earliest vegetation period was completed by 27S08-1 line and the latest by 07G01-17 line. 28S08-1 line was in the same statistical group with 28S08-2 (122 days) and 79M01-1 (122 days) lines. The average vegetation period of the varieties and lines was determined as 140.4 days and 14 lines completed their vegetation before this period. Registered varieties reached maturity later than the lines obtained from Turkey (except 07G01-17 line) under Isparta conditions (Table 1). According to the results , it can be stated that especially the climate and soil conditions of the region where mung bean is grown affect the vegetation period considerably. At the same time,
(Sohail et al., 2016) found that vegetation duration was significantly and positively correlated with plant height (r=0.62). In the literature studies, it was determined that the vegetation period of mung bean varied between 59-162 days (
Begum et al. 2013;
Mehandi et al. 2013;
Tajoddin et al. 2014;
Ahmad et al. 2014).
Plant height
Plant height is one of the most important components that play a significant role on plant yield. In this study, plant height of mung bean lines and varieties varied between 32.5-73.9 cm. The maximum plant height was found in 07A05-3 line and there was no statistical difference with 07G05-5 (72.7 cm) and 07A02-14 (68.1 cm) lines. The shortest plant height was determined in 79M02-1 line and this line was in the same statistical group with 27S08-2 (35.3 cm), 27S08-1 (36.2 cm), 33M02-1 (37.2 cm), 79M01-12 (37.3 cm), 50N01-22 (37.4 cm), 79M02-8 (39.4 cm). The overall average plant height of pure lines and cultivars was 49.98 cm and 9 pure lines and Partow cultivar were above this average (Table 1). Literature reports indicate that mung bean plant height commonly ranges from 24 to 70 cm
(Gul et al., 2008; Begum et al. 2013;
Tajoddin et al. 2014;
Khan et al., 2017), reflecting substantial genetic variability across environments. The broad range observed in our study further supports this variability and suggests strong genotype × environment responsiveness. Importantly, several lines combined desirable yield performance with contrasting growth habits either tall plants with longer vegetation periods or short plants with earlier maturity. Such diverse yet productive phenotypes represent valuable genetic resources for breeding.
First pod height
The highest first pod height of mung bean lines and varieties was determined in line 07G05-5 with 45.2 cm and there was no statistical difference between it and line 07A05-3 with 42.4 cm. The shortest first pod height was determined in line 50N01-22 with 14.2 cm. The general average of the first pod height of pure lines and varieties was determined as 24.3 cm and 9 pure lines and two varieties were above this average (Table 1). In the study, it was determined that the lines with maximum plant height (07A05-3 73.9 cm; 07G05-5 72.7 cm) also had higher first pod height. (
Pekşen et al. 2015) reported a negative and significant correlation between first pod height and harvest index and grain yield. They reported that there were significant increases in the number of inflorescences, plant height and first pod height with the prolongation of the first flowering and pod setting period. In addition,
Akgunduz, (2016) reported that lines with higher plant height also had higher first pod height.
Pods plant-1
In this study, the number of pods per plant of mung bean lines and varieties varied between 16.2-57.4. The highest number of pods was determined in 46G01-2 line and the lowest in Jade-AU variety. The average number of pods of lines and cultivars was 30.3 pods. In terms of the number of pods, the lines were significantly higher than the registered varieties and significant variations were found among the lines (Table 2). The number of pods per plant is a key determinant of yield in legumes (
Vega et al. 2001) and its strong positive association with grain yield in mung bean has been well documented (
Khattak et al. 2002). Previous studies report pod numbers ranging from 7 to 25 per plant (
Akbay et al. 2020;
Gölgül et al. 2023), indicating considerable genetic and environmental influence on this trait. The variation observed among the lines in our study similarly reflects both genotype-dependent differences and field-related factors such as plant density. Lines that consistently produce higher pod numbers represent valuable material for breeding, particularly when integrated into multi-environment evaluations and multi-trait selection frameworks like MGIDI to identify high-yielding recombinant genotypes.
Grains plant-1
In this study, significant (P≤0.01) differences were found between grains plant
-1 of the lines and varieties and the averages of the seeds plant
-1 (Table 2). The number of seeds plant
-1 of the lines and cultivars varied between 154.95-534.37. The highest seeds plant
-1 was determined in line 46G01-2. The lowest seeds plant
-1 was determined in line 27S08-1, while there was no statistical difference between line 79M02-1 and Jade AU variety. The average grains plant-1 of the lines and varieties was 283.64. Grain number is closely related to the number of pods in the plant and generally increase the number of grains in the plant. (
Garje et al. 2014) reported a significant and positive correlation between the grains plant
-1 and the number of pods plant
-1, grains pod
-1 (r=0.53) and grain yield plant
-1 in mung bean.
The averages of the seed pod
-1 of mung bean lines and varieties are given in Table 2. The seed pod
-1 of the lines and varieties varied between 7.71-11.48, the average was 9.57. The highest seed pod
-1 among the lines and varieties was determined in line 07G05-5, followed by 07G01-17 (11.46) and 07A05-1 (11.22). Seeds per pod is a critical yield determining trait in mung bean and previous studies have shown a significant positive association between seeds pod
-1, pods plant
-1 and final grain yield (
Cancı and Toker 2014). In our study, seeds pod
-1 varied markedly among the evaluated lines, indicating substantial genetic variability. Notably, several lines produced more seeds per pod than the registered control varieties, suggesting the presence of superior genetic combinations.
Yield plant-1
The mean yield plant
-1 of mung bean lines and varieties are given in Table 2. Statistically (P≤0.01) significant differences were found between the yield plant
-1 of the lines and varieties. Yield plant
-1 varied between 7.81-23.70 (g plant
-1). The highest yield plant
-1 was determined in line 46G01-2 and was statistically in the same group with line 07A02-14. The lowest yield plant-1 was determined in line 33M02-1. The average yield plant
-1 of the lines and varieties was 14.93 g plant
-1. Yield plant
-1 is a trait that directly affects grain yield and is one of the most important selection criteria in breeding studies.
Plant height, pods plant
-1 and grains plant
-1 are known to be positively associated with yield plant
-1 in mung bean (
Pekşen and Gülümser, 2005).
Ahmad et al. (2014) reported a mean yield of 13.76 g plant
-1 and noted that yield plant
-1 had relatively low heritability (0.42), indicating strong environmental influence. Previous research also shows wide variation in yield plant
-1, ranging from 2.58-5.77 g
(Gul et al., 2008), 6.78-11.57 g (
Mondal et al. 2012), 21.87-45.35 g (
Begum et al. 2013) and 24.19-29.42 g (
Tajoddin et al. 2014), highlighting substantial genetic diversity across studies. In our study, yield plant
-1 similarly differed among the lines, reflecting both genetic variation and sensitivity to environmental conditions during the growing period. Such variability reinforces the importance of multi-environment evaluation and multi-trait selection frameworks when identifying stable, high-yielding genotypes for breeding programs.
Grain yield
Significant differences were found between the grain yield of the lines and varieties used in the study and the averages of grain yield are presented in Table 2. Grain yield varied between 1026.2-2571.0 kg ha
-1. The highest grain yield was determined in line 33M02-17 and there was no statistical difference with line 65M01-2 (2409.2 kg ha
-1). The lowest grain yield was determined in line 79 M 02-1. The average grain yield of lines and varieties was 1884.5 kg ha
-1. This situation shows that these lines are superior in terms of yield and it can be stated that these lines with high grain yield should be taken into consideration during selection.
Grain yield in mung bean is strongly influenced by climatic, edaphic and genetic factors. Previous studies have reported highly variable yields, ranging from 500 to 4500 kg ha
-1 (
Toker et al. 2002;
Cancı and Toker 2005;
Gul et al. 2008;
Sohail et al., 2016), demonstrating substantial genotype × environment interaction for this trait
(Sharma et al., 2022). The variation observed in our study is consistent with this broad yield range and further supports the conclusion that both genetic differences among lines and environmental conditions play crucial roles in determining grain yield.
Principal component analysis (PCA)
Principal component analysis (PCA) signifies the importance of the major contributor to the total variation at each axis of distinction
(Sharma et al., 1998). The results of PCA explained the genetic diversity of the 25 lines and two varieties under study. Three principal components (PC1 to PC3) were extracted from the original data accounting for more than 82% of the total variation. Suggesting these three principal component scores might be used to review the original variables in any further analysis. Corres-pondingly,
Pandiyan et al., (2012) showed that 63.79% variation was justified by the first 3 principal components for 18 quantitative and 37 qualitative characters of 646 mungbean accessions subjected to multivariate analysis. Out of total principal components maintained PC1, PC2 and PC3 with values 36.88%, 34.19% and 11.54% (Table 3 and Fig 4) respectively were contributed more to the total variation.
(Chahal et al., 2002) proposed that attributes with lower absolute value closer to zero influence the clustering less than those with largest absolute value closer to unity within the first principal component. In crop breeding programmes, PCA are very useful in identifying the phenotypic characteristics that contribute higher genetic variations among the genotypes studied, as well as in selecting potential parents for crossing to improve the desired characters for productivity in quantity and quality
(Abna et al., 2012; Basnet et al., 2014).
The first principal component (PC1) accounted for the largest share of variation (36.88%) and was dominated by pods plant
-1, seeds plant
-1 and yield plant
-1. These traits are key yield determinants in mung bean, indicating that PC1 captures variation directly related to reproductive efficiency and overall yield potential. The clustering of these traits within a single component suggests that genotypes combining higher pod and seed numbers tend to express superior yield performance. Similar patterns were reported by
Mehandi et al. (2015), who also found that the primary component in mung bean largely reflects yield-related variability, supporting the consistency of these associations across environments and genetic backgrounds.
PC2 explained an additional 34.19% of total variability and was strongly influenced by plant height, first pod height and seeds pod
-1. This component reflects differences in plant architecture and pod placement traits known to interact with environmental conditions and to influence harvestability and light interception. The substantial contribution of PC2 highlights the presence of meaningful architectural diversity among the lines.
Together, PC1 and PC2 summarize major axes of genetic variation and show that yield components and plant architecture jointly structure diversity in the evaluated material. These results underscore the importance of multi-trait selection approaches. Integrating PCA-derived trait patterns with tools such as MGIDI can improve the identification of genotypes with balanced ideotypes, supporting the development of high-yielding recombinant lines adapted to diverse environments.
Heat map analysis
Heat map is a two-dimensional data visualization approach that reveals the data in rows and columns in a data matrix together with the hierarchical clustering structure
(Barua et al., 2022). The heat map of 2 varities and 25 mung bean lines and 10 traits examined in the study according to the clustering analysis shown in Fig 5. There are two dendrograms in the heat map; one reflects the lines (rows) and the other reflects the traits (columns) that trigger color distribution
(Barua et al., 2022). In the dendrogram formed as a result of clustering analysis, lines were divided into seven groups depending on the traits examined. In these groups, Group 4 had the highest number of lines with 10 lines, followed by Groups 7, while group 1 and 5 had the same number of lines (5). Similarly, Group 2 had only two lines while group three and 6 had the least number of member with 1 lines.
The lines selected by the multitrait genotype-ideotype distance index (MGIDI) were 46G01, 07A05-1, 07A02-14 and 70S01-9 (Fig 6). G13, G04 and G19 were very close to the cut-off point for index three (the red line that indicates the number of lines selected according to the selection pressure), which indicates that these lines have exciting features. Thus, further attention should be paid to the investigation of lines that are extremely close to the cut-off point.
Fig 6 shows the strengths and weaknesses of the lines showed that the first factor FA1 had a higher contribution to the MGIDI of 46G01, suggesting that this genotype performs poorly for the rest of parameters. On the other hand, FA1 had the smallest contribution to lines 07A05-1, 07A02-14 and 70S01-9, indicating these lines were the best-performing among the selected ones for the FA1 traits. FA2 had greater contributions to the MGIDI of 07A05-1 and 07A02-14 and smaller contributions to lines 46G01 and 70S01-9, resulting in these lines having strengths related to FA1 and FA3. Likewise, the contribution of FA3 was higher for the genotype 70S01-9 including the traits DF and PF.
In view of the traits of PPP and YPP and GY in FA1, positive gains are desired, so this lines (46G01) have higher contribution to these traits in comparison to others. In addition to the DF and PF traits in FA3, these lines were shown to have a shorter time to flowering and pod formation. Similarly, the lines 07A05-1 and 07A02-14 were observed to be in the same category (Table 4) as FA2 with superiority in phenological parameters (VD, PH, FPH, SP). these findings are in lined with those of (
Pour-Aboughadareh et al., 2021;
Al-Ashkar et al., 2023;
Gogoi et al., 2024). Based on multivariate and MGIDI analysis the desired features of mung bean lines can be obtained from line 46G01 for better yield, while early maturity performance based line suggested as 70S01-9.
