Knobs in Kashmir maize

The source of the material for this study was a series of collections of local maize varieties from three districts (Anantnag, Pulwama and Baramulla) of Kashmir Valley bearing the same varietal names. In all, fifteen varieties were collected, out of which 4 were collected from Anantnag (Tripachi I, Tripachi III, Vozij IA and Vozij IB), 7 from Pulwama (Tripachi II, Badeh IIa, Badeh IIB, Badeh IV, Niver IVA, Mishri IIC, and Kani IVB) and 4 from Baramulla (Tripachi VI, Badeh V, Niver VA, and Ferozpur VB) districts. Out of these fifteen varieties, 4 are known as Tripachi, 4 as Badeh, 2 as Vozij, 2 as Niver, 1 as Mishri, 1 as Kani and 1 as Ferozpur.

The seed for cytological studies was sown during the year 1973 in the Regional Research Laboratory (Branch), Sanat Nagar, Srinagar. On an average, five plants from each variety were studied. However, in the case of Mishri only one plant could be studied. The material for cytological studies was fixed in a freshly prepared mixture of 1:3 acetic acid and ethyl alcohol (96%) and then stored at low temperature (4-7 C) until worked. Squash preparations were made in 2% acetocarmine. Chromosome morphology was studied at the pachytene stage of meiosis.

Knob number within the varieties of a group showed a lot of variation. Knob number in the Tripachi group varied from a low of 5 for Tripachi VI to a high of 23 for Tripachi II. In the Badeh varieties, there was also great variation. The highest number of knobs (31) of all the fifteen varieties was observed in Badeh V. Niver varieties did not show any difference between each other, but in Vozij varieties, significant differences were observed. The former had 12 and 14 knobs respectively, while the latter possessed 12 and 27. Mishri IIC, Kani IVB and Ferozpur VB possessed 1, 19 and 8 knobs respectively.

The location of the knobs on the two arms was not the same in all the varieties. This difference was of particular interest among the varieties of each group. The short arm of chromosome 1 terminated in a knob in three of the four Tripachi varieties, two of the four Badeh varieties and one of the two Niver varieties. In Tripachi II, Tripachi III and Badeh V the long arm of chromosome 3 had more than two knobs, while Tripachi VI and Badeh IV were knobless in this region. Another interesting feature noted from the knob location was that the short arm of chromosome 1, 4, 7 and 9 ended with a terminal knob in nine, ten, five and eleven varieties, respectively. Similar differences were noticed for other chromosomes of other varieties also.

Taking into consideration the district and group data (Tables 1 and 2), the following similarities/dissimilarities were observed. On the district level (Table 1), Pulwama, Anantnag and Baramulla carried 29, 30 and 31 knobs respectively while the distribution of knob number among five groups (Table 2) ranged from 18 to 32.

Chromosome 1: The long arm of this chromosome bore three intercalary knobs--a, b, and c--in all three districts with varying frequencies. Out of all the groups, the Niver group had only one knob at position a, 3.2 u away from the centromere. In others, three knobs were observed. Short arm knobs were observed in only two districts (Anantnag and Pulwama). These knobs were 3.7 and 5.6 u, respectively, away from the centromere. These knobs were missing from the Badeh and "others" groups. However, a terminal knob on the short arm was present in all the groups as well as in all three districts.

Chromosome 2: The knobs observed on the long arm from Pulwama were 3.5 and 5.0 u away from the centromere, while the other two districts had four knobs. Badeh and Vozij groups had four internal knobs, while in Niver, "others" and Tripachi groups ranged from one to three, respectively. No consistent trend was observed in frequencies. Short arm knobs (a & b) observed on this chromosome from Baramulla had the same frequencies (7.1). In the other two districts, one knob was present on this arm. This arm of the Niver group was knobless, while in Tripachi, Vozij and "others" groups, one knob was observed with varying distances from the centromere. However, the Badeh group had both these knobs.

Chromosome 3: The long arm had three knobs each from Pulwama and Baramulla. In Anantnag, only two of these were observed. However, variations in their respective distances from the centromere and also in their frequencies were observed. On the other hand, two knobs were observed in three out of the five groups. The short arm of this chromosome carried two knobs (a and b) from Baramulla, but only one was observed from Anantnag and Pulwama. This arm was knobless in three of the five groups.

Chromosome 4: Anantnag and Pulwama had three knobs on the long arm, while Baramulla had only two. Tripachi and Vozij groups each had three intercalary knobs, whereas in other groups two knobs were present. The short arm knob was only seen in Baramulla and in the Badeh group. In addition to this, the short arm of this chromosome ended in a terminal knob in all three districts and in all the groups except in the "others" group.

Chromosome 5: On the long arm, Baramulla had three knobs, whereas in the other two districts, two knobs were present. Their respective distances from the centromere were somewhat similar. The Badeh group was the only group which had three knobs, and Vozij the only one which had one knob. All the remaining groups bore two knobs each.

Chromosome 6: The long arm knobs (a, b, and c) observed from Baramulla were 3.0, 3.4 and 4.5 u, respectively, away from the centromere; this arm of the remaining two districts had two knobs each at 4.3, 4.4 and 4.3, 4.5 u, respectively. One, two and three knobs were observed on this arm of Tripachi, Niver, Vozij, "others" and Badeh groups, respectively.

Chromosome 7: Two intercalary knobs were present on the long arm in all three districts, as well as in all groups, except the "others" group. Their relative distances from the centromere were approximately equal. Except for the last two groups, the short arm in all three districts, as well as in the remaining groups, ended in a terminal knob.

Chromosome 8: The long arm of this chromosome possessed two knobs in Anantnag and Pulwama at 2.1, 4.2 and 3.4, 4.7 u, respectively. On the other hand, this arm from Baramulla had only one knob at 4.5 u. Three out of five groups (Tripachi, Vozij and "others") bore three internal knobs, while the other two each had one knob on this arm.

Chromosome 9: Both Anantnag and Pulwama had two knobs on the long arm. Their respective locations were 2.9, 3.2 and 2.1, 3.7 u respectively. However, this arm from Baramulla was knobless. Two out of the five groups possessed two knobs. In others one knob was observed. A simple knob and a terminal knob were observed on the short arm of all three districts, as well as in all five groups. The relative positions of terminal knobs were approximately equal.

Chromosome 10: Except for the Niver group, the long arm of all three districts, as well as the remaining groups, possessed a knob. None of the varieties within a group had a consistent knob number and frequency. On the group level the same sort of variation existed. However, there was some consistency in the total knob numbers among the three districts.

The relative position of the knobs on the two arms was not the same in all varieties. This difference was observed among the five groups and also in the three districts. However a few similarities were also noticed, e.g., knobs present on the long arm of chromosome 7 were approximately at equal distances from the centromere. Likewise, the long arm knobs on chromosome 5 were also at more or less equal distances. The terminal knobs observed on the short arms of chromosomes 1, 4, 7 and 9 had approximately equal relative position within the five groups and also among the three districts for a particular chromosome.

Table 1.

Table 2.

P. N. Jotshi and K. A. Patel


Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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